Water Vapor Distillation Apparatus, Method and System

ABSTRACT

A fluid vapor distillation apparatus. The apparatus includes a source fluid input, and an evaporator condenser apparatus. The evaporator condenser apparatus includes a substantially cylindrical housing and a plurality of tubes in the housing. The source fluid input is fluidly connected to the evaporator condenser and the evaporator condenser transforms source fluid into steam and transforms compressed steam into product fluid. Also included in the fluid vapor distillation apparatus is a heat exchanger fluidly connected to the source fluid input and a product fluid output. The heat exchanger includes an outer tube and at least one inner tube. Also included in the fluid vapor distillation apparatus is a regenerative blower fluidly connected to the evaporator condenser. The regenerative blower compresses steam, and the compressed steam flows to the evaporative condenser where compressed steam is transformed into product fluid.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Non-provisional Application which claimspriority from U.S. Provisional Patent Application 60/933,525, filed Jun.7, 2007.

TECHNICAL FIELD

The present invention relates to water distillation and moreparticularly, to a water vapor distillation apparatus, method, andsystem.

BACKGROUND INFORMATION

A dependable source of clean water eludes vast segments of humanity. Forexample, the Canadian International Development Agency reports thatabout 1.2 billion people lack access to safe drinking water. Publishedreports attribute millions and millions of deaths per year, mostlychildren, to water related diseases. Many water purification techniquesare well known, including carbon filters, chlorination, pasteurization,and reverse osmosis. Many of these techniques are significantly affectedby variations in the water quality and do not address a wide variety ofcommon contaminants, such as bacteria, viruses, organics, arsenic, lead,mercury, and pesticides that may be found in water supplies in thedeveloping world and elsewhere. Some of these systems require access toa supply of consumables, such as filters or chemicals. Moreover, some ofthese techniques are only well suited to centralized, large-scale watersystems that require both a significant infrastructure and highlytrained operators. The ability to produce reliable clean water withoutregard to the water source, on a smaller, decentralized scale, withoutthe need for consumables and constant maintenance is very desirable,particularly in the developing world.

The use of vapor compression distillation to purify water is well knownand may address many of these concerns. However, the poor financialresources, limited technical assets, and low population density thatdoes not make it feasible to build centralized, large-scale watersystems in much of the developing world, also limits the availability ofadequate, affordable, and reliable power to operate vapor compressiondistillation systems, as well as hindering the ability to properlymaintain such systems. In such circumstances, an improved vaporcompression distillation system and associated components that increasesefficiency and production capability, while decreasing the necessarypower budget for system operation and the amount of system maintenancerequired may provide a solution.

SUMMARY

In accordance with one aspect of the present invention, a fluid vapordistillation apparatus is disclosed. The apparatus includes a sourcefluid input, and an evaporator condenser apparatus. The evaporatorcondenser apparatus includes a substantially cylindrical housing and aplurality of tubes in the housing. The source fluid input is fluidlyconnected to the evaporator condenser and the evaporator condensertransforms source fluid into steam and transforms compressed steam intoproduct fluid. Also included in the fluid vapor distillation apparatusis a heat exchanger fluidly connected to the source fluid input and aproduct fluid output. The heat exchanger includes an outer tube and atleast one inner tube. Also included in the fluid vapor distillationapparatus is a regenerative blower fluidly connected to the evaporatorcondenser. The regenerative blower compresses steam, and the compressedsteam flows to the evaporative condenser where compressed steam istransformed into product fluid.

Some embodiments of this aspect of the present invention include one ormore of the following: where the heat exchanger is disposed about thehousing of the evaporator condenser; where the heat exchanger furtherincludes wherein the outer tube is a source fluid flow path and the atleast one inner tube is a product fluid flow path; where the heatexchanger further includes at least three inner tubes; where the atleast three inner tubes are twined to form a substantially helicalshape; where the heat exchanger further includes two ends, and at eachend a connector is attached, whereby the connectors form a connection tothe evaporator condenser; where the evaporator condenser tubes furtherinclude packing inside the tubes; where the packing is a rod; where theevaporator condenser further includes a steam chest fluidly connected tothe plurality of tubes; and where the regenerative blower furthercomprising an impeller assembly driven by a magnetic drive coupling.

In accordance with another aspect of the present invention, a watervapor distillation system is disclosed. The water vapor distillationsystem includes a source fluid input, and an evaporator condenserapparatus. The evaporator condenser apparatus includes a substantiallycylindrical housing and a plurality of tubes in the housing. The sourcefluid input is fluidly connected to the evaporator condenser and theevaporator condenser transforms source fluid into steam and transformscompressed steam into product fluid. Also included in the fluid vapordistillation apparatus is a heat exchanger fluidly connected to thesource fluid input and a product fluid output. The heat exchangerincludes an outer tube and at least one inner tube. Also included in thefluid vapor distillation apparatus is a regenerative blower fluidlyconnected to the evaporator condenser. The regenerative blowercompresses steam, and the compressed steam flows to the evaporativecondenser where compressed steam is transformed into product fluid.

The water vapor distillation system also includes a Stirling engineelectrically connected to the water vapor distillation apparatus. TheStirling engine at least partially powers the water vapor distillationapparatus.

Some embodiments of this aspect of the present invention include wherethe Stirling engine includes at least one rocking drive mechanism wherethe rocking drive mechanism includes: a rocking beam having a rockerpivot, at least one cylinder and at least one piston. The piston ishoused within a respective cylinder. The piston is capable ofsubstantially linearly reciprocating within the respective cylinder.Also, the drive mechanism includes at least one coupling assembly havinga proximal end and a distal end. The proximal end is connected to thepiston and the distal end is connected to the rocking beam by an endpivot. The linear motion of the piston is converted to rotary motion ofthe rocking beam. Also, a crankcase housing the rocking beam and housinga first portion of the coupling assembly is included. A crankshaftcoupled to the rocking beam by way of a connecting rod is also included.The rotary motion of the rocking beam is transferred to the crankshaft.The machine also includes a working space housing the at least onecylinder, the at least one piston and a second portion of the couplingassembly. A seal is included for sealing the workspace from thecrankcase.

Additionally, some embodiments of this aspect of the present inventioninclude any one or more of the following: where the seal is a rollingdiaphragm; also, where the coupling assembly further includes a pistonrod and a link rod; where the piston rod and link rod are coupledtogether by a coupling means; where the heat exchanger is disposed aboutthe housing of the evaporator condenser; where the heat exchangerfurther comprising wherein the outer tube is a source fluid flow pathand the at least one inner tube is a product fluid flow path; where theheat exchanger further comprising at least three inner tubes; where theevaporator condenser further includes a steam chest fluidly connected tothe plurality of tubes; and where the regenerative blower furtherincludes an impeller assembly driven by a magnetic drive coupling.

These aspects of the invention are not meant to be exclusive and otherfeatures, aspects, and advantages of the present invention will bereadily apparent to those of ordinary skill in the art when read inconjunction with the appended claims and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reading the following detailed description, takentogether with the drawings wherein:

FIG. 1 is an isometric view of the water vapor distillation apparatus;

FIG. 1A is an exploded view of the exemplary embodiment of thedisclosure;

FIG. 1B is a cross-section view of the exemplary embodiment;

FIG. 1C is a cross-section view of the exemplary embodiment;

FIG. 1D is an assembly view of the exemplary embodiment;

FIG. 1E is a detail view of the exemplary embodiment of the frame;

FIG. 1F is an assembly view of an alternate embodiment;

FIG. 1G is an assembly view of an alternate embodiment;

FIG. 1H is an assembly view of an alternate embodiment;

FIG. 2 is an assembly view of the exemplary embodiment of thetube-in-tube heat exchanger assembly;

FIG. 2A is an exploded view one embodiment of the tube-in-tube heatexchanger;

FIG. 2B is an isometric view of the exemplary embodiment of thetube-in-tube heat exchanger from the back;

FIG. 2C is an isometric view of the exemplary embodiment of thetube-in-tube heat exchanger from the front;

FIG. 2D is a cross-section view of one embodiment of the tube-in-tubeheat exchanger;

FIG. 2E is an exploded view of an alternate embodiment of a tube-in-tubeheat exchanger;

FIG. 2F is a cut away view of one embodiment of the tube-in-tube heatexchanger illustrating the helical arrangement of the inner tubes;

FIG. 2G is an exploded view of an alternate embodiment of a tube-in-tubeheat exchanger;

FIG. 2H is an isometric view of the exemplary embodiment of thetube-in-tube heat exchanger;

FIG. 2I is an isometric view of the exemplary embodiment of thetube-in-tube heat exchanger;

FIG. 2J is an exploded view of an alternate embodiment of thetube-in-tube heat exchanger configuration;

FIG. 2K is an assembly view of an alternate embodiment of thetube-in-tube heat exchanger configuration;

FIG. 2L is an assembly view of an alternate embodiment of thetube-in-tube heat exchanger configuration;

FIG. 2M is a detail view of an alternate embodiment of the tube-in-tubeheat exchanger configuration;

FIG. 2N is a detail view of an alternate embodiment of the tube-in-tubeheat exchanger configuration;

FIG. 2O is a schematic of an alternate embodiment of the tube-in-tubeheat exchanger configuration;

FIG. 2P is an assembly view of an alternate embodiment of the heatexchanger;

FIG. 2Q is an exploded view of an alternate embodiment of the heatexchanger;

FIG. 2R is a section view of an alternate embodiment of the heatexchanger;

FIG. 3 is an exploded view of the connectors for the fitting assemblythat attaches to the tube-in-tube heat exchanger;

FIG. 3A is a cross-section view of fitting assembly for the tube-in-tubeheat exchanger;

FIG. 3B is a cross-section view of fitting assembly for the tube-in-tubeheat exchanger;

FIG. 3C is an isometric view of the exemplary embodiment for the firstconnector;

FIG. 3D is a cross-section view of the exemplary embodiment for thefirst connector;

FIG. 3E is a cross-section view of the exemplary embodiment for thefirst connector;

FIG. 3F is a cross-section view of the exemplary embodiment for thefirst connector;

FIG. 3G is an isometric view of the exemplary embodiment for the secondconnector;

FIG. 3H is a cross-section view of fitting assembly for the tube-in-tubeheat exchanger;

FIG. 3I is a cross-section view of the exemplary embodiment for thesecond connector;

FIG. 3J is a cross-section view of the exemplary embodiment for thesecond connector;

FIG. 4 is an isometric view of the exemplary embodiment of theevaporator/condenser assembly;

FIG. 4A is a cross-section view of the exemplary embodiment of theevaporator/condenser assembly;

FIG. 4B is an isometric cross-section view of the exemplary embodimentof the evaporator/condenser;

FIG. 4C is an isometric view of an alternate embodiment of theevaporator/condenser assembly;

FIG. 5 is an assembly view of the exemplary embodiment of the sump;

FIG. 5A is an exploded view of the exemplary embodiment of the sump;

FIG. 6 is an isometric detail view of the flange for the sump assembly;

FIG. 7 is an exploded view of the exemplary embodiment of theevaporator/condenser;

FIG. 7A is an top view of the exemplary embodiment of theevaporator/condenser assembly;

FIG. 7B shows the rate of distillate output for an evaporator as afunction of pressure for several liquid boiling modes;

FIG. 8 is an isometric view of the exemplary embodiment of the tube forthe evaporator/condenser;

FIG. 9 is an exploded view of the tube and rod configuration for theevaporator/condenser;

FIG. 9A is an isometric view of the exemplary embodiment of the rod forthe evaporator/condenser;

FIG. 10 is an isometric view of the exemplary embodiment of the sumptube sheet;

FIG. 10A is an isometric view of the exemplary embodiment of the uppertube sheet;

FIG. 11 is a detail view of the top cap for the evaporator/condenser;

FIG. 12 is an isometric view of the exemplary embodiment of the steamchest;

FIG. 12A is an isometric view of the exemplary embodiment of the steamchest;

FIG. 12B is a cross-section view of the exemplary embodiment of thesteam chest;

FIG. 12C is an exploded view of the exemplary embodiment of the steamchest;

FIG. 12D is an isometric view of an alternate embodiment;

FIG. 12E is a cross-section view of the exemplary embodiment of thesteam chest;

FIG. 12F is a cross-section view of the exemplary embodiment of thesteam chest;

FIG. 13 is an assembly view of an alternate embodiment of theevaporator/condenser;

FIG. 13A is a cross-section view of the alternate embodiment of theevaporator/condenser;

FIG. 13B is an assembly view of an alternate embodiment of theevaporator/condenser illustrating the arrangement of the tubes;

FIG. 13C is a cross-section view of the alternate embodiment of theevaporator/condenser illustrating the arrangement of the tubes;

FIG. 13D is an isometric view of the alternate embodiment of theevaporator/condenser without the sump installed;

FIG. 13E is an exploded view of the alternate embodiment of theevaporator/condenser;

FIG. 14 is an isometric view of the mist eliminator assembly;

FIG. 14A is an isometric view of the outside of the cap for the misteliminator;

FIG. 14B is an isometric view of the inside of the cap for the misteliminator;

FIG. 14C is a cross-section view of the mist eliminator assembly;

FIG. 14D is a cross-section view of the mist eliminator assembly;

FIG. 15 is assembly view of the exemplary embodiment of a regenerativeblower;

FIG. 15A is bottom view of the exemplary embodiment of the regenerativeblower assembly;

FIG. 15B is a top view of the exemplary embodiment of the regenerativeblower assembly;

FIG. 15C is an exploded view of the exemplary embodiment of theregenerative blower;

FIG. 15D is a detailed view of the outer surface of the upper section ofthe housing for the exemplary embodiment of the regenerative blower;

FIG. 15E is a detailed view of the inner surface of the upper section ofthe housing for the exemplary embodiment of the regenerative blower;

FIG. 15F is a detailed view of the inner surface of the lower section ofthe housing for the exemplary embodiment of the regenerative blower;

FIG. 15G is a detailed view of the outer surface of the lower section ofthe housing for the exemplary embodiment of the regenerative blower;

FIG. 15H is a cross-section view of the exemplary embodiment of theregenerative blower;

FIG. 15I is a cross-section view of the exemplary embodiment of theregenerative blower;

FIG. 15J is a cross-section view of the exemplary embodiment of theregenerative blower;

FIG. 15K is a schematic of the exemplary embodiment of the regenerativeblower assembly;

FIG. 15L is a cross-section view of the exemplary embodiment of theregenerative blower;

FIG. 16 is a detailed view of the impeller assembly for the exemplaryembodiment of the regenerative blower;

FIG. 16A is a cross-section view of the impeller assembly;

FIG. 17 is an assembly view of the alternate embodiment of aregenerative blower;

FIG. 17A is an assembly view of the alternate embodiment of aregenerative blower;

FIG. 17B is a cross-section view of the alternate embodiment of theregenerative blower assembly;

FIG. 17C is a cross-section view of the alternate embodiment of theregenerative blower assembly;

FIG. 17D is a cross-section view of the alternate embodiment of theregenerative blower assembly;

FIG. 17E is an exploded view of the alternate embodiment of theregenerative blower;

FIG. 17F is an assembly view of the impeller housing;

FIG. 17G is an exploded view of the impeller housing;

FIG. 17H is a cross-section view of the alternate embodiment for theimpeller housing assembly;

FIG. 17I is a cross-section view of the alternate embodiment for theimpeller housing assembly;

FIG. 17J is a bottom view of the lower section of the impeller housing;

FIG. 17K is a detail view of the inner surface of the lower section ofthe impeller housing;

FIG. 17L is a top view of the upper section of the impeller housingassembly;

FIG. 17M is a top view of the upper section of the housing for theimpeller assembly without the cover installed;

FIG. 17N is a detailed view of the inner surface of the upper section ofthe housing for the impeller assembly;

FIG. 18 is a detailed view of the impeller assembly for the alternateembodiment of the regenerative blower;

FIG. 18A is a cross-section view of the impeller assembly;

FIG. 19 is an assembly view of the level sensor assembly;

FIG. 19A is an exploded view of the exemplary embodiment of the levelsensor assembly;

FIG. 19B is cross-section view of the settling tank within the levelsensor housing;

FIG. 19C is cross-section view of the blowdown sensor and product levelsensor reservoirs within the level sensor housing;

FIG. 19D is an assembly view of an alternate embodiment of the levelsensor assembly;

FIG. 19E is an exploded view of an alternate embodiment of the levelsensor assembly;

FIG. 19F is a cross-section view of an alternate embodiment of the levelsensor assembly;

FIG. 19G is a schematic of the operation of the level sensor assembly;

FIG. 19H is an alternate embodiment of the level sensor assembly;

FIG. 20 is an isometric view of level sensor assembly;

FIG. 20A is cross-section view of the level sensor assembly;

FIG. 21 is an isometric view of the front side of the bearing feed-waterpump;

FIG. 21A is an isometric view of the back side of the bearing feed-waterpump;

FIG. 22 is a schematic of the flow path of the source water for theexemplary embodiment of the water vapor distillation apparatus;

FIG. 22A is a schematic of the source water entering the heat exchanger;

FIG. 22B is a schematic of the source water passing through the heatexchanger;

FIG. 22C is a schematic of the source water exiting the heat exchanger;

FIG. 22D is a schematic of the source water passing through theregenerative blower;

FIG. 22E is a schematic of the source water exiting the regenerativeblower and entering

FIG. 23 is a schematic of the flow paths of the blowdown water for theexemplary embodiment of the water vapor distillation apparatus;

FIG. 23A is a schematic of the blowdown water exitingevaporator/condenser assembly and entering the level sensor housing;

FIG. 23B is a schematic of the blowdown water filling the settling tankwithin the level sensor housing;

FIG. 23C is a schematic of the blowdown water filling the blowdown levelsensor reservoir within the level sensor housing;

FIG. 23D is a schematic of the blowdown water exiting the level sensorhousing and entering the strainer;

FIG. 23E is a schematic of the blowdown water exiting the strainer andentering the heat exchanger;

FIG. 23F is a schematic of the blowdown water passing through the heatexchanger;

FIG. 23G is a schematic of the blowdown water exiting the heatexchanger;

FIG. 24 is a schematic of the flow paths of the product water for theexemplary embodiment the water vapor distillation apparatus;

FIG. 24A is a schematic of the product water exiting theevaporator/condenser assembly and entering the level sensor housing;

FIG. 24B is a schematic of the product water entering the product levelsensor reservoir within the level sensor housing;

FIG. 24C is a schematic of the product water exiting the product levelsensor reservoir and entering the heat exchanger;

FIG. 24D is a schematic of the product water passing through the heatexchanger;

FIG. 24E is a schematic of the product water exiting the heat exchanger;

FIG. 24F is a schematic of the product water entering the bearing-feedwater reservoir within the level sensor housing;

FIG. 24G is a schematic of the product water exiting the level sensorhousing and entering the bearing feed-water pump;

FIG. 24H is a schematic of the product water exiting the bearingfeed-water pump and entering the regenerative blower;

FIG. 24I is a schematic of the product water exiting the regenerativeblower and entering the level sensor housing;

FIG. 25 is a schematic of the vent paths for the exemplary embodimentthe water vapor distillation apparatus;

FIG. 25A is a schematic of the vent path allowing air to exit theblowdown sensor reservoir and enter the evaporative/condenser;

FIG. 25B is a schematic of the vent path allowing air to exit theproduct sensor reservoir and enter the evaporative/condenser;

FIG. 25C is a schematic of the vent path allowing air to exit theevaporator/condenser assembly;

FIG. 26 is a schematic of the low-pressure steam entering the tubes ofthe evaporator/condenser assembly from the sump;

FIG. 26A is a schematic of the low-pressure steam passing through thetubes of the evaporator/condenser assembly;

FIG. 26B is a schematic of the wet-low-pressure steam exiting the tubesof the evaporator/condenser assembly and entering the steam chest;

FIG. 26C is a schematic of the wet-low-pressure steam flowing throughthe steam chest of the evaporator/condenser assembly;

FIG. 26D is a schematic of the creation of blowdown water as thelow-pressure steam passing through the steam chest;

FIG. 26E is a schematic of the dry-low-pressure steam exiting the steamchest and entering the regenerative blower;

FIG. 26F is a schematic of the dry-low-pressure steam passing throughthe regenerative blower;

FIG. 26G is a schematic of the high-pressure steam exiting theregenerative blower;

FIG. 26H is a schematic of the high-pressure steam entering the steamtube;

FIG. 26I is a schematic of the high-pressure steam exiting the steamtube and entering the evaporator/condenser chamber;

FIG. 26J is a schematic of the creation of product water from thehigh-pressure steam condensing within the evaporator/condenser chamber;

FIG. 27 is a chart illustrating the relationship between thedifferential pressure across the regenerative blower and the amount ofenergy required to produce one liter of product;

FIG. 28 is a chart illustrating the relationship between the productionrate of product and the number of heat transfer tubes within theevaporator/condenser assembly;

FIG. 29 is a chart illustrating the production rate of product water ofthe evaporator/condenser assembly as a function of the amount of heattransfer surface area with the evaporator/condenser chamber;

FIG. 30 is a chart illustrating the efficiency of heat transfer surfacesfor a varying amount of heat transfer tubes within theevaporator/condenser chamber as related to the change in pressure acrossthe regenerative blower;

FIG. 31 is a chart illustrating the production rate and the amount ofenergy consumed by the evaporator/condenser assembly at differentpressure differentials across the regenerative blower;

FIG. 32 is a cross-sectional and top view of a rotor and stator inaccordance with a particular embodiment showing the support structurefor the input, the vanes and chambers between the vanes, and therotating drive shaft;

FIG. 32A is a side top view of a rotor and stator corresponding to theembodiment shown in FIG. 32, showing the support structures for theinput and output, the vanes, the eccentric configuration within thehousing unit, and the drive shaft;

FIG. 32B is a top view of a rotor and stator corresponding to theembodiment shown in FIGS. 32 and 32A, showing support structures forinput and output, the vanes, the eccentric configuration within thehousing unit, and the drive shaft;

FIG. 32C is a cross-sectional view of a rotor and stator correspondingto the embodiment shown in FIGS. 32, 32A, and 32B showing vanes, driveshaft, and bearings;

FIG. 32D is a cross-sectional view of a liquid ring pump according toone embodiment showing a capacitive sensor;

FIG. 32E is a cross-sectional view of a liquid ring pump according toone embodiment showing the eccentric rotor, rotor vanes, drive shaftwith bearings, the rotating housing unit for the liquid ring pump, thestill housing, and the cyclone effect and resulting mist and waterdroplet elimination from the steam;

FIG. 32F is a schematic diagram of An alternate embodiment for theliquid ring pump;

FIG. 32G is a top view of an alternate embodiment for a rotor showingmultiple vanes and chambers between the vanes, and intake and exit holesin each individual chamber;

FIG. 32H is further detail of a liquid ring pump showing the stationaryintake port and the rotating drive shaft, rotor and housing unit;

FIG. 32I is a view of a seal which may be present between the stationaryand rotor sections of a liquid ring pump separating the intake orificefrom the exit orifice;

FIG. 33 is side view of a backpressure regulator in accordance with oneembodiment;

FIG. 33A is a diagonal view of the backpressure regulator shown in FIG.33;

FIG. 33B is a side view of an alternate embodiment of the backpressureregulator having a vertically positioned port;

FIG. 33C is a diagonal view of the backpressure regulator shown in FIG.33B;

FIG. 33D is a diagonal view of an alternate embodiment of thebackpressure regulator;

FIG. 33E is a close-up view of section C of FIG. 33D, depicting a notchin the port of the backpressure regulator;

FIG. 33F is a cutaway side view of one embodiment of the backpressureregulator;

FIG. 33G is a close up view of section E of FIG. 33F, depicting a smallopening in an orifice of the backpressure regulator;

FIG. 34 is a schematic of a backpressure regulator implemented within aapparatus;

FIG. 35 is a schematic of an alternate embodiment for a water vapordistillation apparatus;

FIG. 35A is a detailed schematic of an alternate embodiment for thelevel sensor housing illustrating an external connecting valve betweensource and blowdown fluid lines;

FIG. 36 is a view of one face of the pump side of a fluid distributionmanifold;

FIG. 36A is a view of a second face of the pump side of a fluiddistribution manifold;

FIG. 36B is a view of one face of the evaporator/condenser side of afluid distribution manifold;

FIG. 36C is a view of a second face of the evaporator/condenser side ofa fluid distribution manifold;

FIG. 37 is a top view of a coupler of an alternate embodiment of afitting assembly;

FIG. 37A is a side view of an alternate embodiment of a fitting assemblyin FIG. 37;

FIG. 38 is a cross-sectional view of alternate embodiment of theevaporator/condenser having individual heating layers and ribs;

FIG. 38A is a detail of a cross-section of an alternate embodiment ofthe evaporator/condenser showing how the ribs effectively partition thesteam/evaporation from the liquid/condensation layers;

FIG. 39 is a schematic diagram of an alternate embodiment for the heatexchanger;

FIG. 39A is schematic diagram of an alternative embodiment for the heatexchanger;

FIG. 40 is a schematic overview of the an alternate embodiment of thewater vapor distillation apparatus including a pressure measurement ofthe system using a cold sensor;

FIG. 41 is shows a view of a flip-filter with the intake stream andblowdown stream flowing through filter units, each filter unit rotatingaround a pivot joint about a center axis;

FIG. 41A shows flip filter housing;

FIG. 41B is detail view of the flip-filter in FIG. 41;

FIG. 41C is an alternative embodiment of a multi-unit flip filter;

FIG. 41D is a schematic of an alternate embodiment of a flip-filter;

FIG. 41E is a schematic of the flow path of one embodiment of theflip-filter;

FIG. 41F is a schematic illustrating a manual switch for changing waterflow through individual units of a flip-filter in FIG. 41E;

FIG. 42 is a depiction of a monitoring system for distributed utilities;

FIG. 43 is a depiction of a distribution system for utilities;

FIG. 44 is a conceptual flow diagram of a possible embodiment of asystem incorporating an alternate embodiment of the water vapordistillation apparatus;

FIG. 44A is a schematic block diagram of a power source for use with thesystem shown in FIG. 44;

FIGS. 51A-51E depict the principle of operation of a Stirling cyclemachine;

FIG. 52 shows a view of a rocking beam drive in accordance with oneembodiment;

FIG. 53 shows a view of a rocking beam drive in accordance with oneembodiment;

FIG. 54 shows a view of an engine in accordance with one embodiment;

FIGS. 55A-55D depicts various views of a rocking beam drive inaccordance with one embodiment;

FIG. 56 shows a bearing style rod connector in accordance with oneembodiment;

FIGS. 57A-57B show a flexure in accordance with one embodiment;

FIG. 58 shows a four cylinder double rocking beam drive arrangement inaccordance with one embodiment;

FIG. 59 shows a cross section of a crankshaft in accordance with oneembodiment;

FIG. 510A shows a view of an engine in accordance with one embodiment;

FIG. 510B shows a crankshaft coupling in accordance with one embodiment;

FIG. 510C shows a view of a sleeve rotor in accordance with oneembodiment;

FIG. 510D shows a view of a crankshaft in accordance with oneembodiment;

FIG. 510E is a cross section of the sleeve rotor and spline shaft inaccordance with one embodiment;

FIG. 510F is a cross section of the crankshaft and the spline shaft inaccordance with one embodiment;

FIG. 510G are various views a sleeve rotor, crankshaft and spline shaftin accordance with one embodiment;

FIG. 511 shows the operation of pistons of an engine in accordance withone embodiment;

FIG. 512A shows an unwrapped schematic view of a working space andcylinders in accordance with one embodiment;

FIG. 512B shows a schematic view of a cylinder, heater head, andregenerator in accordance with one embodiment;

FIG. 512C shows a view of a cylinder head in accordance with oneembodiment;

FIG. 513A shows a view of a rolling diaphragm, along with supporting topseal piston and bottom seal piston, in accordance with one embodiment;

FIG. 513B shows an exploded view of a rocking beam driven engine inaccordance with one embodiment;

FIG. 513C shows a view of a cylinder, heater head, regenerator, androlling diaphragm, in accordance with one embodiment;

FIGS. 513D-513E show various views of a rolling diaphragm duringoperation, in accordance with one embodiment;

FIG. 513F shows an unwrapped schematic view of a working space andcylinders in accordance with one embodiment;

FIG. 513G shows a view of an external combustion engine in accordancewith one;

FIGS. 514A-514E show views of various embodiments of a rollingdiaphragm;

FIG. 515A shows a view of a metal bellows and accompanying piston rodand pistons in accordance with one embodiment;

FIGS. 515B-515D show views of metal bellows diaphragms, in accordancewith one embodiment;

FIGS. 515E-515G show a view of metal bellows in accordance with variousembodiments;

FIG. 515H shows a schematic of a rolling diaphragm identifying variousload regions;

FIG. 515I shows a schematic of the rolling diaphragm identifying theconvolution region;

FIG. 516 shows a view of a piston and piston seal in accordance with oneembodiment;

FIG. 517 shows a view of a piston rod and piston rod seal in accordancewith one embodiment;

FIG. 518A shows a view of a piston seal backing ring in accordance withone embodiment;

FIG. 518B shows a pressure diagram for a backing ring in accordance withone embodiment;

FIGS. 518C and 518D show a piston seal in accordance with oneembodiment;

FIGS. 518E and 518F show a piston rod seal in accordance with oneembodiment;

FIG. 519A shows a view of a piston seal backing ring in accordance withone embodiment;

FIG. 519B shows a pressure diagram for a piston seal backing ring inaccordance with one embodiment;

FIG. 520A shows a view of a piston rod seal backing ring in accordancewith one embodiment;

FIG. 520B shows a pressure diagram for a piston rod seal backing ring inaccordance with one embodiment;

FIG. 521 shows views of a piston guide ring in accordance with oneembodiment;

FIG. 522 shows an unwrapped schematic illustration of a working spaceand cylinders in accordance with one embodiment;

FIG. 523A shows a view of an engine in accordance with one embodiment;

FIG. 523B shows a view of an engine in accordance with one embodiment;

FIG. 524 shows a view of a crankshaft in accordance with one embodiment;

FIGS. 525A-525C show various configurations of pump drives in accordancewith various embodiments;

FIG. 526A show various views of an oil pump in accordance with oneembodiment;

FIG. 526B shows a view of an engine in accordance with one embodiment;

FIG. 526C shows another view of the engine depicted in FIG. 526B;

FIGS. 527A and 527B show views of an engine in accordance with oneembodiment;

FIG. 527C shows a view of a coupling joint in accordance with oneembodiment;

FIG. 527D shows a view of a crankshaft and spline shaft of an engine inaccordance with one embodiment;

FIG. 528A shows an illustrative view of a generator connected to oneembodiment of the apparatus;

FIG. 528B shows a schematic representation of an auxiliary power unitfor providing electrical power and heat to a water vapor distillationapparatus; and

FIG. 528C shows a schematic view of a system according to oneembodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Definitions. As used in this description and the accompanying claims,the following terms shall have the meanings indicated, unless thecontext otherwise requires.

The term “fluid” is used herein to include any type of fluid includingwater. Thus, although the exemplary embodiment and various otherembodiments are described herein with reference to water, the scope ofthe apparatus, system and methods includes any type of fluid. Also,herein, the term “liquid” may be used to indicate the exemplaryembodiment, where the fluid is a liquid.

The term “evaporator condenser” is used herein to refer to an apparatusthat is a combination evaporator and condenser. Thus, a structure isreferred to as an evaporator condenser where the structure itself servesas both. The evaporator condenser structure is referred to herein as anevaporator/condenser, evaporator condenser or evaporator and condenser.Further, in some instances, where either the evaporator or the condenseris being referred to individually, it should be understood that the termis not limiting and refers to the evaporator condenser structure.

The term “unclean water” is used herein to refer to any water wherein itis desired to make cleaner prior to consuming the water.

The term “cleaner water” is used herein to refer to water that iscleaner as product water than as source water.

The term “source water” refers to any water that enters the apparatus.

The term “product water” refers to the cleaner water that exits theapparatus.

The term “purifying” as used herein, and in any appended claims, refersto reducing the concentration of one or more contaminants or otherwisealtering the concentration of one or more contaminants.

The term “specified levels” as used herein refers to some desired levelof concentration, as established by a user for a particular application.One instance of a specified level may be limiting a contaminant level ina fluid to carry out an industrial or commercial process. An example iseliminating contaminant levels in solvents or reactants to a levelacceptable to enable an industrially significant yield in a chemicalreaction (e.g., polymerization). Another instance of a specified levelmay be a certain contaminant level in a fluid as set forth by agovernmental or intergovernmental agency for safety or health reasons.Examples might include the concentration of one or more contaminants inwater to be used for drinking or particular health or medicalapplications, the concentration levels being set forth by organizationssuch as the World Health Organization or the U.S. EnvironmentalProtection Agency.

The term “system” as used herein may refer to any combination ofelements, including but not limited to, a water vapor distillationapparatus (which may be referred to as a water system or a water vapordistillation system) and a water vapor distillation apparatus togetherwith a power source, such as a Stirling engine.

Herein is disclosed an apparatus for distilling unclean water known assource water into cleaner water known as product water. The apparatuscleanses the source water by evaporating the water to separate theparticulate from the source water. The term “purifying” as used herein,and in any appended claims, refers to substantially reducing theconcentration of one or more contaminants to less than or equal tospecified levels or otherwise substantially altering the concentrationof one or more contaminants to within a specified range.

The source water may first pass through a counter flow tube-in-tube heatexchanger to increase the temperature of the water. Increasing thetemperature of the source water reduces the amount of thermal energyrequired to evaporate the water within the evaporator/condenser. Thesource water may receive thermal energy from the other fluid streamspresent in the heat exchanger. Typically, these other streams have ahigher temperature than the source water motivating thermal energy toflow from the higher temperature streams to the lower temperature sourcewater.

Receiving the heated source water is the evaporator area of theevaporator/condenser assembly. This assembly evaporates the source waterto separate the contaminants from the water. Thermal energy may besupplied using a heating element and high-pressure steam. Typically, theheating element will be used during initial start-up, thus under normaloperating conditions the thermal energy will be provided by thehigh-pressure steam. The source water fills the inner tubes of theevaporator area of the evaporator/condenser. When the high-pressuresteam condenses on the outer surfaces of these tubes thermal energy isconducted to the source water. This thermal energy causes some of thesource water to evaporate into low-pressure steam. After the sourcewater transforms into a low-pressure steam, the steam may exit theoutlet of the tubes and pass through a separator. The separator removesany remaining water droplets within the steam ensuring that thelow-pressure steam is dry before entering the compressor.

Upon exiting the evaporator area of the evaporator/condenser thelow-pressure steam enters a compressor. The compressor createshigh-pressure steam by compressing the low-pressure steam. As the steamis compressed the temperature of the steam increases. With the steam atan elevated temperature and pressure the steam exits the compressor.

The high-pressure steam enters the condenser area of theevaporator/condenser. As the steam fills the internal cavity the steamcondenses on the tubes contained within the cavity. The high-pressuresteam transfers thermal energy to the source water within the tubes.This heat transfer causes the steam to condense upon the outer surfaceof the tubes creating product water. The product water is collected inthe base of the condenser area of the evaporator/condenser. The productwater leaves the evaporator area of the evaporator/condenser and entersthe level sensor housing.

The level sensor housing contains level sensors for determining theamount of product and blowdown water within the apparatus. These sensorsallow an operator to adjust the amount of product water being producedor the amount of incoming source water depending on the water levelswithin the apparatus.

The water vapor distillation apparatus as described herein with respectto various embodiments may further be used in conjunction with aStirling engine to form a water vapor distillation system. The powerneeded by the water vapor distillation apparatus may be provided by aStirling engine electrically connected to the water vapor distillationapparatus.

Referring to FIG. 1, one embodiment of the water vapor distillationapparatus 100 is shown. For the purposes of this description, theembodiment shown in FIG. 1 will be referred to as the exemplaryembodiment. Other embodiments are contemplated some of which will bediscussed herein. The apparatus 100 may include a heat exchanger 102,evaporator/condenser assembly 104, regenerative blower 106, level sensorassembly 108, a bearing feed-water pump 110, and a frame 112. See alsoFIGS. 1A-E for additional views and cross sections of the water vapordistillation apparatus 100.

Referring to FIGS. 1F-H, these figures illustrate alternate embodimentsof the water vapor distillation apparatus 100. FIG. 1F depicts anapparatus 120 having an alternate configuration of theevaporator/condenser assembly 122. Similarly, FIG. 1G discloses anapparatus having another configuration of the evaporator/condenserassembly 132. Similarly, FIG. 1H illustrates another embodiment of theapparatus not including the level sensor assembly 108 and bearingfeed-water pump 110 from FIGS. 1-1E.

Heat Exchanger

Referring now to FIGS. 2-2A, in the exemplary embodiment of the watervapor distillation apparatus, the heat exchanger may be a counter flowtube-in-tube heat exchanger assembly 200. In this embodiment, heatexchanger assembly 200 may include an outer tube 202, a plurality ofinner tubes 204 and a pair of connectors 206 illustrated in FIG. 2A.Alternate embodiments of the heat exchanger assembly 200 may not includeconnectors 206.

Still referring to FIGS. 2-2A, the heat exchanger assembly 200 maycontain several independent fluid paths. In the exemplary embodiment,the outer tube 202 contains source water and four inner tubes 204. Threeof these inner tubes 204 may contain product water created by theapparatus. The fourth inner tube may contain blowdown water.

Still referring to FIGS. 2-2A, the heat exchanger assembly 200 increasesthe temperature of the incoming source water and reduces the temperatureof the outgoing product water. As the source water contacts the outersurface of the inner tubes 204, thermal energy is conducted from thehigher temperature blowdown and product water to the lower temperaturesource water through the wall of the inner tubes 204. Increasing thetemperature of the source water improves the efficiency of the watervapor distillation apparatus 100 because source water having a highertemperature requires less energy to evaporate the water. Moreover,reducing the temperature of the product water prepares the water for useby the consumer.

Still referring to FIGS. 2-2A, in the exemplary embodiment the heatexchanger 200 is a tube-in-tube heat exchanger having an outer tube 202having several functions. First, the outer tube 202 protects andcontains the inner tubes 204. The outer tube 202 protects the innertubes 204 from corrosion by acting as a barrier between the inner tubes204 and the surrounding environment. In addition, the outer tube 202also improves the efficiency of the heat exchanger 200 by preventing theexchange of thermal energy to the surrounding environment. The outertube 202 insulates the inner tubes 204 reducing any heat transfer to orfrom the surrounding environment. Similarly, the outer tube 202 mayresist heat transfer from the inner tubes 204 focusing the heat transfertowards the source water and improving the efficiency of the heatexchanger 200.

Still referring to FIGS. 2-2A, the outer tube 202 may be manufacturedfrom any material, but low thermal conductivity is desirable. The lowthermal conductivity is important, because the outer tube 202 insulatesthe inner tubes 204 from the surrounding environment. The low thermalconductivity of the outer tube improves the efficiency of the heatexchanger, because a low thermal conductive material reduces thermalenergy losses or gains to the surrounding environment. In addition, lowthermal conductive material lowers the amount of thermal energy that maybe transferred from the inner tubes 204 to the outer tube 202. Thisresistance to heat transfer allows more thermal energy to be transferredto the source water rather than escaping from the apparatus through theouter tube 202. Thus an outer tube 202 manufactured from a materialhaving a low thermal conductivity allows more thermal energy to betransferred to the source water rather than lost or gained to thesurrounding environment.

Still referring to FIGS. 2-2A, in the exemplary embodiment the outertube 202 is manufactured from a clear silicone. In addition to having alow thermal conductivity, silicone material is also corrosion resistant.This is an important characteristic to prevent corrosion of the heatexchanger 200. The source water within the outer tube 202 may containchemicals and/or other highly reactive materials. These materials maycause outer tubing 202 made from other materials to breakdown reducingthe service life of the heat exchanger 200. In alternate embodiments,the outer tube 202 may be manufactured from other materials, such asplastic or rubber having high temperatures resistance. Also, in oneembodiment the outer tube 202 is made from convoluted tubing to enhancemixing, which increases heat transfer efficiency.

Referring now to FIGS. 2B-C, another desirable characteristic is for theouter tubing 202 to be sufficiently elastic to support installation ofthe heat exchanger 200 within the water vapor distillation apparatus100. In some applications space for the distillation apparatus may belimited by other environmental or situational constraints. For example,in the exemplary embodiment the heat exchanger 200 is wrapped around theevaporator/condenser. In other embodiments, the heat exchanger may alsobe integrated into the insulated cover of the water vapor distillationapparatus to minimize heat lost or gained from the environment. In theexemplary embodiment the heat exchanger 200 is configured in a coil asshown in FIGS. 2B-C. To achieve this configuration the inner tubes 204are slid into the outer tube 202 and then wound around a mandrel. Anelastic outer tube 202 assists with positioning the ends of the heatexchanger 200 at particular locations within the apparatus. Thus, havingan elastic outer tube 202 may facilitate in the installation of the heatexchanger 200 within the water vapor distillation apparatus 100.

Still referring to FIGS. 2B-C, the elasticity of the outer tubing 202material may also be affected by the wall thickness. Tubing having athick wall thickness has less flexibility. The thicker wall thickness,however, may improve the thermal characteristics of the tubing, becausethe thicker wall has greater resistance heat transfer. In addition, thewall thickness of the tubing must be sufficient to withstand theinternal pressures generated by the source water within the tubing.Tubing having an increased wall thickness, however, has decreasedelasticity and increases the size of the heat exchanger assembly.Thicker walled tubing requires a larger bend radius affecting theinstallation the heat exchanger 200. Conversely, tubing having toolittle wall thickness tends to kink during installation. This distortionof the tubing may restrict the flow of source water through the outertube 202 causing a reduction in the efficiency of the heat exchanger200.

The diameter of the outer tube 202 may be any diameter capable ofcontaining a plurality of inner tubes 204. The larger the diameter,however, lowers the flexibility of the tubing. Any reduction inflexibility may adversely affect the installation of the heat exchangerinto the water vapor distillation apparatus 100. In the exemplaryembodiment, the diameter of the outer tube 202 is one inch. Thisdiameter allows the tube-in-tube heat exchanger 200 to be wrapped aroundthe evaporator/condenser 104 upon final installation and contains fourinner tubes 204 for transporting product and blowdown water. Inalternate embodiments the heat exchanger may have as few as two innertubes 204. Similarly, in other embodiments the heat exchanger may havemore than four inner tubes 204.

Now referring to FIGS. 2A and 2D, the inner tubes 204 may provideseparate flow paths for the source, product, and blowdown water. In theexemplary embodiment, these tubes contain product and blowdown water.However, in other embodiments, the inner tubes may contain additionalfluid streams. The inner tubes 204 separate the clean and safe productwater from the contaminated and unhealthy source and blowdown water. Inthe exemplary embodiment, there are three inner tubes 204 for productwater and one inner tube 204 for blowdown. The source water travelswithin the outer tube 202 of the heat exchanger 200. In various otherembodiments, the number of inner tubes may vary, i.e., greater number ofinner tubes may be included or a lesser number of inner tubes may beincluded.

Still referring to FIGS. 2A and 2D, the inner tubes 204 conduct thermalenergy through the tube walls. Thermal energy flows from the hightemperature product and blowdown water within the inner tubes 204through the tube walls to the low temperature source water. Thus, theinner tubes 204 are preferably made from a material having a highthermal conductivity, and additionally, preferably from a material thatis corrosion resistant. In the exemplary embodiment, the inner tubes 204are manufactured from copper. The inner tubes 204 may be manufacturedfrom other materials such as brass or titanium with preference thatthese other materials have the properties of high thermal conductivityand corrosion resistance. For applications where the source and blowdownwater may be highly concentrated, such as sea water, the inner tubes 204may be manufactured from but not limited to copper-nickel, titanium orthermally conductive plastics.

In addition to the tubing material, the diameter and thickness of thetubing may also affect the rate of thermal energy transfer. Inner tubing204 having a greater wall thickness may have less thermal efficiencybecause increasing the wall thickness of the tubing mat also increasethe resistance to heat transfer. In the exemplary embodiment, the innertubes 204 have 0.25 inch outside diameter. Although a thinner wallthickness increases the rate of heat transfer, the wall thickness mustbe sufficient to be shaped or formed without distorting. Thinner walledtubing is more likely to kink, pinch or collapse during formation. Inaddition, the wall thickness of the inner tubes 204 must be sufficientto withstand the internal pressure created by the water passing throughthe tubes.

Still referring to FIGS. 2A and 2D, additional methods for improving therate of heat transfer of the inner tubes 204 may include unequal innertube diameters and extended surfaces on the inner tubes to enhance heattransfer (fins, pins, ribs . . . ). In addition, the outer tube 202 mayhave a textured interior surface causing turbulence in the flow of thesource water to enhance heat transfer. The rate of heat transfer isincreased because the texture surface produces a turbulent flow withinthe tube 202. The turbulence increases the amount of water that contactsthe outer surfaces of the inner tubes 204 where the heat transferoccurs. In contrast, without a texture surface the water may flow in amore laminar manner. This laminar flow will allow only a limited amountof water to contact the outer surfaces of the inner tubes 204. Theremaining water not in contact with the inner tubes 204 receives lessthermal energy because the convective thermal transfer between the waternear the inner tubes and the remaining water is not as efficient as theheat transfer near the outer surface of the inner tubes 204. Someexamples of textured surfaces may include but are not limited todimples, fins, bumps or grooves. In another embodiment may shrink to fitouter tube to increase shell side flow velocity and therefore enhanceheat transfer.

Referring now to FIG. 2E, typically, the inner tubes 204 are positionedparallel to one another. In some embodiments, however, the inner tubes204 are braided or twined together to form a helix or a substantiallyhelical shape as illustrated in FIGS. 2F-G. The helix shape increasesthe amount of surface area for heat transfer, because the length of theinner tubes 204 is longer than inner tubes 204 of the parallelarrangement. The increased surface area provides more area for heattransfer, thus increasing the efficiency of the heat exchanger 200. Inaddition, the helical shape may cause a turbulent flow of source waterwithin the outer tubing 202 improving the heat transfer efficiency aspreviously described. In the exemplary embodiment, the heat exchanger200 has four inner tubes 204 arranged in a helical shape illustrated onFIGS. 2H-I.

The total length of the tubes-in-tube heat exchanger 200 is governed bythe desired efficiency of the apparatus. A heat exchanger 200 having alonger length yields better efficiency. In the exemplary embodiment, theheat exchanger 200 is approximately 50 feet long. This yieldsapproximately 90% efficiency. Alternatively, a length of 25 feet yieldsan efficiency of approximately 84%.

Referring now to FIGS. 2, 2J, and 2K the heat exchanger assembly 200 mayalso include a connector 206 at either end of the heat exchanger 200. Inthe exemplary embodiment, the heat exchanger 200 has two connectorslocated at either end of the assembly. These connectors 206 along withthe outer tube 202 define an inner cavity for containing the sourcewater. In addition, the connectors attach to the ends of the inner tubes204 and provide separate fluid paths for the product and blowdown waterto enter and/or exit the heat exchanger 200. The connectors 206 allowthe heat exchanger assembly to be mechanically connected to theevaporator/condenser and other apparatus components. In some embodimentsan extension 207 may be included within the heat exchanger 200 toprovide an additional port to remove or supply water to the heatexchanger 200.

Referring now to FIGS. 2L-O, these figures illustrate an alternateembodiment of the heat exchanger 200 having three inner tubes 204passing through connectors 208. The connectors 208 are sealed andattached to the inner tubes 204 and the outer tube 202 at either end ofthe heat exchanger 200 to contain the source water inside the outer tube202. An o-ring may be installed within the connectors 208 to seal theinterface between the connector 208 and the inner tubes 204. This typeseal may allow the inner tubes 204 to move freely and independently ofthe connector 208. Furthermore, the inner tubes 204 may be arranged in ahelical shape as shown in FIG. 2N.

Referring to FIGS. 2P-R, these figures illustrate an alternateembodiment for the heat exchanger 210. In this embodiment, the heatexchanger 210 is a plate heat exchanger having metal plates 212 andplastic plates 214. The metal plates 212 may be manufacture from anymetallic materials, such as stainless steel. Other embodiments mayinclude but are not limited to plates manufactured from titanium ormetal alloy. The plastic plates 214 are made from any type of plasticcapable of performing. In one embodiment, the plate heat exchanger 210is made from alternately metal and plastic plates. In other embodimentsmetal plates 212 may be followed by two or more plastic plates 214 asillustrated in FIG. 2R. The plate heat exchanger 210 may begin and/orend with a plate 216 manufacture from the same or different material asthe previous plate. In alternate embodiments, plate 216 may bemanufactured from a metallic or plastic material. The metal plates 212consist of two metal plates stacked onto one another creating channelsfor fluid flow as shown in FIG. 2R.

Referring now to FIG. 3, the exemplary embodiment of the counter flowtube-in-tube heat exchanger 200 may include a fitting assembly 300. Thefitting assembly supports installation of the heat exchanger 200 withinthe water vapor distillation apparatus 100. In addition, the fittingassembly 300 allows the heat exchanger 200 to be easily disconnectedfrom the apparatus for maintenance. The assembly may consist of a firstconnector 302 (Also identified as connector 206 of FIG. 2) and a secondconnector 310 shown on FIG. 3. See also, FIGS. 3A-B for cross-sectionviews of the fitting assembly 300.

Still referring to FIG. 3, in the exemplary embodiment of the fittingassembly 300 is manufactured from brass. Other materials may be used tomanufacture the fitting assembly 300 including, but are not limited tostainless steel, plastic, copper, copper nickel or titanium. Forinstallation purposes, having the fitting assembly manufactured fromsimilar material as the tubing that attaches to the assembly ispreferred. Similar materials allow for the assembly to be installedwithin the water vapor distillation apparatus using a soldering orwelding technique. The fitting assembly 300 is preferably manufacturedfrom materials that are corrosion resistant and heat resistant (250°F.). In addition, the materials preferably allows for a fluid tightconnection when the assembly is installed. For applications where thesource and blowdown water may be highly concentrated, such as sea water,the fitting assembly 300 may be manufactured from but not limited tocopper-nickel or titanium.

Still referring to FIG. 3, the first connector 302 includes a first end304 and a second end 306. The first end 304 attaches to the heatexchanger 200 as shown in FIGS. 2-2A. The connector may be attached tothe heat exchanger 200 by clamping the outer tube 202 using a hose clampagainst the outer surface of the first end 304 of the connector 302. Theinner tubes 204 of the heat exchanger 200 may also connect to theconnector 302 at the first end 304. These tubes may be soldered to theheat exchanger side of the connector 302. Other methods of attachmentmay include, but are not limited to welding, press fitting, mechanicalclamping or insert molding. See also FIGS. 3A-3B for cross-section viewsof fitting assembly 300.

Now referring to FIG. 3C, in this embodiment the first end 304 of theconnector 302 may have five ports. Three ports may be in fluidconnection with one another as shown on FIGS. 3D-E. This configurationmay combine multiple streams of product water into one stream. Multiplestreams of product water increases the amount of heat transfer from theproduct water to the source water, because there is more product waterwithin the heat exchanger to provide thermal energy to the source water.The remaining ports are separate and provide fluid pathways for blowdownand source water illustrated in FIGS. 3E-F. Alternate embodiments maynot have any ports in fluid connection with one another.

Still referring to FIG. 3C, connector 302 has a second end 306 formating with the second connector 310. This second end 306 may have threeports providing flow paths for product, source and blowdown water. Theproduct flow path may include an extension 308. The extension 308supports assembling connectors 302 and 310 together because theextension 308 allows for the o-ring groove within the body of the secondconnector 310 rather than on the mating surface 310. Having the o-ringgroove within the body of the second connector 310 allows the flow pathsthrough the connector assembly to be positioned near one another withouthaving overlapping sealing areas.

Now referring to FIGS. 3G-H, the second connector 310 includes a firstend 312 and a second end 314. The first end 312 mates with the firstconnector 302 as shown on FIG. 3. This end may also include an extension316 as shown in FIG. 3G. The extension 316 allows for the o-ring grooveto be located within the body of the first connector 302 rather thanwithin the surface of end 306 of the first connector 302. In addition,this connector may have a leak path 318 on the first end 312. This pathis located around the port for the product water to prevent source orblowdown water from entering the product stream. Blowdown and sourcewater may contain contaminants that affect the quality and safety of theproduct water. The leak path allows the blowdown and source water toleave the fitting rather than entering the product stream through adrain 320 illustrated on FIGS. 3G-I. In addition to the drain 320, theexemplary embodiment may include three independent fluid paths withinthe connector 310 illustrated on FIGS. 3I-J.

The first connector 302 may be assembled to the second connector 310using a Marmon clamp to allow for serviceability of the apparatus. Thistype of clamp provides an even clamping force and ease ofdisassembly/reassembly of the connection. Other methods of assemblingthe connectors together include, but are not limited using a C-clamp orfasteners (i.e. bolts and nuts). In addition, the circumference of theconnectors 302 and 310 may be tapered, as shown on FIGS. 3E-F and 31-J,to receive the clamp during installation of the fitting assembly 300. Inother embodiments, the fitting assembly 300 may be permanently joined bywelding or soldering the connectors together.

Evaporator Condenser

Now referring to FIGS. 4-4B, the exemplary embodiment of the evaporatorcondenser (also herein referred to as an “evaporator/condenser”)assembly 400 may consist of an evaporator/condenser chamber 402 having atop and bottom. The chamber 402 may include a shell 410, an upper tubesheet 414 and a lower tube sheet 412. Attached to the lower tube sheet412 is a sump assembly 404 for holding incoming source water. Similarly,attached to the upper tube sheet 414 is an upper flange 406. This flangeconnects the steam chest 408 to the evaporator/condenser chamber 402.Within the evaporator/condenser chamber 402 are a plurality of rods 416where each rod is surrounded by a tube 418 as illustrated in FIGS. 4Aand 4B. The tubes 418 are in fluid connection with the sump 404 andupper flange 406. See also FIG. 4C illustrating an alternate embodimentof the evaporator/condenser assembly 420.

Now referring to FIG. 5, the sump assembly 500 (also identified as 404on FIG. 4) may include an upper housing 502, a lower housing 504, adrain fitting 506, drain pipe 508, and heating element 510. See alsoFIG. 5A for an exploded view of the sump assembly 500 and FIG. 6 fordetailed view of the upper housing 502. The sump assembly 500 containsand heats source water, as well as collects particulate carried by thesource water. When the source water changes state from a fluid to avapor particulate is left behind and is collected in the sump assembly500.

Still referring to FIGS. 5-5A, the sump assembly 500 may be made frommaterial that is corrosion and high-temperature resistant. A corrosionresistant material is preferred because the sump is exposed to hightemperatures, moisture, and corrosive source water. In the exemplaryembodiment the sump is manufactured from stainless steel. In analternate embodiment the sump may be manufactured from RADEL® or otherhigh-temperature plastic in conjunction with an alternate configurationfor attaching the heating element 510. For applications where the sourcewater may be highly concentrated, such as sea water, the sump assembly500 may be manufactured from but not limited to titanium, copper-nickel,naval bronze, or high-temperature plastic.

Still referring to FIGS. 5-5A, the source water may be heated using aheating element 510 of the sump assembly 500. The heat element 510increases the temperature of the source water during initial start up ofthe water vapor distillation apparatus 100. This element providesadditional thermal energy causing the source water to change from afluid to a vapor. In the exemplary embodiment, the heat element 510 maybe a 120 Volt/1200 Watt resistive element electric heater.

Still referring to FIGS. 5-5A, the sump assembly 500 may include abottom housing 504 having an angled lower surface in order to assistwith the collection of particulate. The bottom housing 504 may have anyangle sufficient to collect the particulate in one area of the housing.In the exemplary embodiment the bottom housing 504 has a 17 degreeangled-lower surface. In other embodiments, the bottom housing 504 mayhave a flat bottom.

Still referring to FIGS. 5-5A, the exemplary embodiment may include adrain assembly consisting of a drain fitting 506 and a drain pipe 508.The drain assembly provides access to inside of the evaporator area ofthe evaporator/condenser to remove particulate buildup without having todisassemble the apparatus. The drain assembly may be located near thebottom of the sump to reduce scaling (buildup of particulates) on thetubes inside the evaporator/condenser. Scaling is prevented by allowingperiodic removal of the scale in the sump assembly 500. Having lessparticulate in the sump assembly 500 reduces the likelihood thatparticulate will flow into the tubes of the evaporator/condenser. In theexemplary embodiment the drain assembly is positioned to receiveparticulate from the angled-lower surface of the bottom housing 504. Thedrain assembly may be made of any material that may be attached to thebottom housing 504 and is corrosion and heat resistant. In the exemplaryembodiment, the drain fitting 506 is a flanged sanitary fittingmanufactured from stainless steel.

Still referring to FIGS. 5-5A, attached to the drain fitting 506 may bea drain pipe 508. The drain pipe 508 provides a fluid path way forparticulate to travel from the drain fitting 506 out of theevaporator/condenser assembly 400. The drain pipe 508 may bemanufactured from any material, with preference that the material iscorrosion and heat resistant and is capable of being attached to thedrain fitting 506. In the exemplary embodiment, the drain pipe 508 ismanufactured from stainless steel. The diameter of the drain pipe 508 ispreferably sufficient to allow for removal of particulate from the sumpassembly 500. A larger diameter pipe is desirable because there is aless likelihood of the drain pipe 508 becoming clogged with particulatewhile draining the sump assembly 500.

Now referring to FIG. 7, the exemplary embodiment of theevaporator/condenser chamber 700 (also identified as 402 of FIG. 4) mayinclude a shell 702 (also identified as 410 of FIGS. 4A-B, a lowerflange 704 (also identified as 502 of FIGS. 5 and 600 of FIG. 6), alower-tube sheet 706 (also identified as 412 of FIGS. 4A-B), a pluralityof tie rods 708, a plurality of tubes 710 (also identified as 418 ofFIGS. 4A-B), an upper flange 712 (also identified as 406 of FIG. 4) andan upper-tube sheet 714 (also identified as 414 of FIGS. 4A-B). See alsoFIG. 7A for an assembly view evaporator/condenser chamber 700.

Still referring to FIG. 7, the shell 702 defines an internal cavitywhere thermal energy is transferred from the high-pressure steam to thesource water. This heat transfer supports the phase change of the sourcewater from a fluid to a vapor. In addition, the heat transfer alsocauses the incoming steam to condense into product water. The shell 702may be manufactured from any material that has sufficient corrosionresistant and strength characteristics. In the exemplary embodiment, theshell 702 is manufactured from fiberglass. It is preferable that theshell has an inner diameter sufficient to contain the desired number oftubes 710. Within the internal cavity of the shell is a plurality oftubes 710 having surface area for transferring thermal energy from thehigh-pressure steam entering the chamber to source water within thetubes 710.

Still referring to FIG. 7, the evaporator/condenser chamber 700 definesan inner cavity for the condensation of high-pressure steam. Within thiscavity is a plurality of tubes 710 that transfer thermal energy fromhigh-pressure steam to source water within the tubes as the steamcondensing upon outer surfaces of the tubes. The heat transfer throughthe tube walls causes the source water to undergo a phase change througha process called thin film evaporation as described in U.S. PatentApplication Pub. No. US 2005/0183832 A1 published on Aug. 25, 2005entitled “Method and Apparatus for Phase Change Enhancement,” thecontents of which are hereby incorporated by reference herein.

Still referring to FIG. 7, in the tubes 710 of the evaporator/condenser,a Taylor bubble may be developed which has an outer surface including athin film in contact with an inner surface of the tubes 710. The Taylorbubble is heated as it rises within the tube so that fluid in the thinfilm transitions into vapor within the bubble.

Now referring to FIG. 7B, typically an evaporator may operate in eitherof two modes: pool boiling mode or thin film mode. In thin film boiling,a thin film of fluid is created on the inner wall of the tubesfacilitating heat transfer from the tube wall to the free surface of thefluid. The efficiency of phase change typically increases for thin filmmode as compared to pool boiling mode. FIG. 7B shows the difference inthe rate of distillate production as a function of condenser pressurefor pool boiling and thin film boiling under similar conditions for arepresentative evaporator. The bottom curve 70 corresponds to poolboiling while the middle curve 75 corresponds to thin film boiling. Aswill be noted from these two curves, thin film boiling mode offerssignificantly higher efficiency than pool boiling mode. Thin filmboiling is more difficult to maintain than pool boiling, however. Thinfilm evaporation is typically achieved using apparatus that includesvery small openings. This apparatus may easily clog, particularly whenthe source fluid contains contaminants. Additionally, in thin film modethe water level is typically held just marginally above the tops of thetubes in a vertical tube-type evaporator. For reasons such as this, theapparatus may also be sensitive to movement and positioning of theapparatus.

Referring back to FIG. 7, in the exemplary embodiment the tubes 710 havean outer diameter of 0.75 inches and may be manufactured from copper. Inalternate embodiments, the tubes 710 may be manufactured from othermaterials including but not limited to nickel copper or other compositematerials. In various other embodiments, the diameter of the tubes maydifferent, i.e., may be smaller or larger. For possible applicationswhere the source water may be seawater, the tubes 710 may bemanufactured from copper-nickel or titanium material. These materialshave high corrosion resistant properties to maintain the heat transfercharacteristics of the tubes when exposed to highly concentrated sourcewater, such as, salt water. The diameter of the tubes 710 may also varydepending on many variables. The diameter of the tubes 710 may belimited by the inner diameter of the shell 702 and the desired amount ofheat transfer efficiency. Another constraint may be serviceability. Asmaller diameter is more difficult to remove scale from because thereduced diameter restricts access to the inner surfaces of the tubewalls. The length of the tubes 710 may be determined by the length ofthe inner cavity defined by the shell 702 and the thickness of the tubesheets 706 and 714. In the exemplary embodiment the tubes 710 extendbeyond the ends of the tube sheets into the lower flange 704 and upperflange 712.

Referring now to FIG. 8, in the exemplary embodiment the tubes 800 (alsoidentified as 710 of FIG. 7A-B) have a bead 802 near each end. The bead802 prevents the tubes 800 from sliding through the apertures in thelower tube sheet 706 and the upper tube sheet 714.

Referring now to FIG. 9, improved efficiency of a phase change operationmay be achieved by providing packing within the evaporator/condensertubes 904. The introduction of such packing may allow the evaporator totake on some of the characteristics of thin film mode, due to theinteraction between the fluid, the packing and the tube 904. The packingmay be any material shaped such that the material preferentially fillsthe volume of a tube 904 near the tube's longitudinal axis versus thevolume near the tube's interior wall. Such packing material serves toconcentrate the vapor near the walls of the tube for efficient heatexchange. For example, in the exemplary embodiment the packing maycomprise a rod 902. Each rod 902 may be of any cross-sectional shapeincluding a cylindrical or rectangular shape. The cross-sectional areaof each packing rod 902 may be any area that will fit within thecross-section of the tube. The cross-sectional area of each rod 902 mayvary along the rod's length. A given rod 902 may extend the length of agiven evaporator tube 904 or any subset thereof. It is preferable thatthe rod material be hydrophobic and capable of repeated thermal cycling.In the exemplary embodiment the rods 902 are manufactured from glassfiber filled RYTON® or glass fiber filled polypropylene.

Still referring to FIG. 9, each rod 902 may be positioned anywherewithin the tube 904 including preferentially in the upper portion of thetube. In one specific embodiment, each rod is approximately half thelength of the associated tube and is positioned approximately in the tophalf of the tube. The top curve 80 in FIG. 7B shows the increase inboiling efficiency for thin film boiling for a representative evaporatorwhere the evaporator tubes include packing material in approximately thetop half of the tubes. With such packing, the phase change efficiency isalso, advantageously, much less sensitive to changes in the fluid levelabove the tubes, the orientation of the tubes with respect to thevertical, the feed pressure for the tubes and other operating parametersfor the evaporator. In the exemplary embodiment the rods 902 haveapproximately the same length as the tubes 904.

Referring now to FIG. 9A, in the exemplary embodiment, the rods 902 mayhave a plurality of members 906 extending out from the center and alongthe longitudinal axis of the rod 902. These members 906 maintain the rod902 within the center of the tube 904 to produce the most efficient flowpath for the source water. Any number of members may be used, however,it is preferential that there is a sufficient number to maintain the rod902 in the center of the tube 904. In alternate embodiments, the rods902 may not have members 906. In alternate embodiments the rod 902 maybe held in place within the tube 904 by wrapping the rod 902 in a wireor cross drilling holes within the rod 902 to support installation ofpins to position the rod 902 within the tube 904.

Referring back to FIG. 7, the tubes 710 (Also identified as 800 of FIG.8 and 904 of FIG. 9) are secured in place by the pair of tube sheets 706and 714. These sheets are secured to each end of the shell 702 using thetie rods 708. The tube sheets 706 and 714 have a plurality of aperturesthat provide a pathway for the source water to enter and exit the tubes710. When the tubes 710 are installed within the chamber 700, theapertures within the tube sheets 706 and 714 receive the ends of thetubes 710. The lower tube sheet 706 (also identified as 1002 on FIG. 10)is attached to the bottom of the shell 702. See FIG. 10 for a detailview of the lower tube sheet. The upper tube sheet 714 (also identifiedas 1004 on FIG. 10A) is attached to the top of the shell 702. See FIG.10 A for a detail view of the upper tube sheet. Both tube sheets havesimilar dimensions except that the upper tube sheet 714 has anadditional aperture located in the center of the sheet. This apertureprovides an opening for the high-pressure steam to enter theevaporator/condenser chamber 700.

Still referring to FIG. 7, in the exemplary embodiments the upper-tubesheet 714 and the lower-tube sheet 706 may be manufactured from RADEL®.This material has low creep, hydrolytic stability, thermal stability andlow thermal conductivity. Furthermore, tube sheets manufactured fromRADEL® may be formed by machining or injection molding. In alternateembodiments, the tube sheets may be manufactured from other materialsincluding but are not limited to G10.

Still referring to FIG. 7, the size of the plurality of apertures withinthe tube sheets 706 and 714 for receiving the tubes 710 is governed bythe outside diameter of the tubes 710. These apertures must besufficient to receive the end of the tubes 710 and also include a seal.Typically, an o-ring groove is provided within the tube sheets toreceive an o-ring. This o-ring provides a water-tight seal between theinner tubes 710 and the tube sheets 706 and 714. In addition, this typeof seal simplifies construction, facilitates the use of dissimilarmaterials within the evaporator/condenser, and allows the tubes 710 tomove during repeated thermal cycles. This seal prevents the productwater from entering into the sump 500 of FIG. 5 or source water enteringthe chamber 700. In alternate embodiments, the tubes 710 may beinstalled within the apertures of the tube sheets 706 and 714 by theusing the methods of, but not limited to soldering, welding, pressfitting, bonding (i.e. silicone, RTV, epoxy . . . ), brazing or swagingdepending on the tube sheet material.

Now referring to FIG. 10, in the exemplary embodiment the o-ring groovesare located at various depths in the tube sheets 1002 and 1004. Thedifferent depths of the o-ring grooves allows the tubes 710 to bepositioned more closely together, because the o-ring grooves fromadjacent tubes do not overlap one another. Overlapping o-ring grooves donot provide a sufficient seal, thus each o-ring groove must beindependent of the other o-ring grooves within the tube sheet. As aresult of varying the location of the o-ring grooves at different depthswithin the tube sheet, adjacent o-ring grooves do not overlap oneanother allowing the tubes to be positioned closer together. Thus havingthe tubes 710 located closer to one another allows more tubes to bepositioned within the evaporator/condenser chamber 700.

Referring back to FIG. 7, the tube sheets 706 and 714 are also securedto the lower flange 704 and the upper flange 712 using the tie rods 708.The lower flange 704 (also identified as 502 of FIGS. 5 and 600 of FIG.6) connects the sump 500 of FIG. 5 to the evaporator/condenser chamber700 of FIG. 7. In addition, the lower flange 704 provides a fluidconnection for the source water within the sump to the inlet of tubes710 positioned on the lower tube sheet 706. The lower flange 704 mayhave any height with preference that the height is sufficient to allowfor an even distribution of the source water entering the tubes 710.Typically a flange having a height of one to two inches provides for aneven distribution of source water into the tubes 710. In alternateembodiments the height of the flange may be larger to increase thecapacity of the sump to collect particulate.

Still referring to FIG. 7, the upper flange 712 (also identified as 1100of FIG. 11) provides a fluid connection between the outlet of the tubes710 and the steam chest 408 of FIG. 4. In addition, the upper flange 712collects the source water removed from the low-pressure steam as thesteam passes through the steam chest 408. This water is then transferredout of the apparatus through the blowdown port 1102 located within theside of the upper flange 1100 of FIG. 11.

Still referring to FIG. 7, the lower flange 704 and upper flange 712 maybe manufactured out of any material having sufficient structuralstrength and corrosion and temperature resistant properties. In oneembodiment, the flanges may be manufactured from RADEL®. In theexemplary embodiment the flanges may be manufactured from nickel-platedaluminum. In other embodiments the lower flange may be manufacture frommaterial including but not limited to stainless steel, titanium andcopper-nickel.

Referring to FIG. 7-7A, located near the outer edge of the lower flange704 and the upper flange 712 is a plurality of apertures to receive thetie rods 708. These rods are axially positioned on a bolt circleconcentric to and along the outside perimeter of the shell 702. Thelength of the tie rods 708 is governed by the length of the shell 702and the thickness of the lower-tube sheet 706, lower flange 704, upperflange 712 and upper-tube sheet 714. The tie rods 708 may have threadedends for attaching a threaded fastener onto each end of the rod securingthe components of the evaporator/condenser together. In addition, thetie rods 708 may be manufactured from any material that is of sufficientstrength for the purpose, such as, stainless steel. Tie rods 708 may bemanufactured from other materials including, but not limited to bronze,titanium, fiberglass composite materials, and carbon steel. In theexemplary embodiment, the tie rods 708 may have flats machined near eachend to provide a flat surface for receiving a device to hold the rods inplace during installation.

Referring now to FIGS. 12-12C, connected to the upper flange 1100 (alsoidentified as 712 of FIG. 7) may be a steam chest 1200 (also identifiedas 408 in FIG. 4). In the exemplary embodiment, the steam chest 1200 mayinclude a base 1202, a steam separator assembly 1204, a cap 1206 and asteam tube 1208. The base 1202 defines an internal cavity for receivingthe low-pressure steam created within the tubes 710 of the evaporatorarea of the evaporator/condenser chamber 700. The base 1202 may have anyheight such that there is sufficient space to allow water dropletscontained within the vapor to be separated. The height of the steamchest allows the water droplets carried by the steam and forciblyejected from outlets of the tubes 710 from the rapid release of steambubbles to decelerate and fall back towards the upper flange 712 (alsoidentified as 1100 on FIG. 11).

Still referring to FIGS. 12-12C, within the base 1202 may be a steamseparator assembly 1204. This assembly consists of a basket and mesh(not shown in FIGS. 12-12C). The basket contains a quantity of wiremesh. In the exemplary embodiment, the steam separator assembly 1204removes water droplets from the incoming low-pressure steam bymanipulating the steam through a layer of wire mesh. As the steam passesthrough the mesh the water droplets start to collect on the surfaces ofthe mesh. These droplets may contain contaminants or particulate. As thedroplets increase in size, the water falls onto the bottom of thebasket. A plurality of apertures may be located in the bottom of thebasket to allow water to collect within the upper flange 712. Inaddition, these apertures provide a fluid path way for low-pressuresteam to enter the steam separator assembly 1204. In addition, the wiremesh provides a barrier from the splashing blowdown water located withinthe upper flange 712 of the evaporator/condenser.

Still referring to FIGS. 12-12C, in alternate embodiments the steamseparator assembly 1204 may contain a series of plates for collectingthe water droplets from the low-pressure water vapor as the vapor passesthrough or around each plate. The plates manipulate the steam to causewater droplets to collect onto the plates. The water is collected in theassembly because the plates are arranged creating sharp bends in theflow path of the steam. These bends reduce the velocity of and changethe direction of the steam. The water droplet may continue along theirinitial trajectory due to momentum. The droplets may then impact thewalls or plates of the assembly where the droplets are collected. Whenenough droplets have collected on the walls or plates of the assembly,the water droplets may fall down towards the upper flange 406 of theevaporator/condenser.

Still referring to FIGS. 12-12C, the base 1202 may also have anobservation window 1210. This window allows people operating theapparatus to visually observe the internals of the steam chest todetermine if the apparatus is functioning properly. In otherembodiments, the steam chest 1200 may not include an observation window1210. This alternate embodiment is illustrated in FIG. 12D. In stillother embodiments, the size and shape of the window may vary. In someembodiments, the steam chest may include multiple windows.

In the exemplary embodiment, the steam separator assembly may bemanufactured from stainless steel. Other materials may be used, however,with preference that those materials have corrosion and high temperatureresistant properties. Other types of materials may include, but are notlimited to RADEL®, titanium, copper-nickel, plated aluminum, fibercomposites, and high temperature plastics.

Still referring to FIGS. 12-12C, attached to the base 1202 is the cap1206. The cap and base define the internal cavity for separating thewater from the low-pressure steam. In addition, the cap 1206 may havetwo ports, an outlet port 1211 and inlet port 1212 shown on FIGS. 12B,12E and 12F. The outlet port provides a fluid path way for the drylow-pressure steam to exit the steam chest 1200. In the exemplaryembodiment, the outlet port 1211 is located near the top surface of thecap 1206 because the locating the port away from the outlets of thetubes 710 of the evaporator/condenser promotes dryer steam. In alternateembodiments, however, the outlet port 1211 may have a different locationwithin the cap 1206. Similarly, the inlet port 1212 provides a fluidpath way for high-pressure steam to enter the high-pressure steam tube1208 within the steam chest 1200. In the exemplary embodiment, the inletport 1212 is located near the top surface of the cap 1206. In alternateembodiments, the inlet port 1212 may have a different location withinthe cap 1206. In the exemplary embodiment, the cap 1206 is manufacturedfrom plated aluminum. Other types of materials may include, but are notlimited to stainless steel, plastics, titanium and copper-nickel. Thesize of these ports may affect the pressure drop across the compressor.

Still referring to FIGS. 12-12C, connected to the inlet port 1212 withinthe steam chest 1200 is a steam tube 1208. This tube provides a fluidpath way for the high-pressure steam to pass through the steam chest andenter the condenser area of the evaporator/condenser chamber. The innerdiameter of the steam tube 1208 may be any size, such that the tube doesnot adversely affect the flow of high-pressure steam from theregenerative blower to the evaporator/condenser chamber. In theexemplary embodiment the steam tube 1208 may be manufactured fromstainless steel. Other materials may be used to manufacture the steamtube 1208, but these materials must have sufficient corrosion resistantand high temperature resistant properties. Such materials may include,but are not limited to plated aluminum, plastics, titanium andcopper-nickel. For applications where the source water may be highlyconcentrated, such as sea water, the steam chest 1200 may bemanufactured from but not limited to titanium, nickel, bronze,nickel-copper and copper-nickel.

Referring now to FIGS. 13-13C, an alternate embodiment of theevaporator/condenser assembly 1300 is shown. In this embodiment, theevaporator/condenser assembly 1300 includes a sump 1302, anevaporator/condenser chamber 1304, a mist eliminator assembly 1306, aplurality of tie rids 1308, a lower flange 1310 and an upper flange1312. See FIG. 13D for a detail view of the evaporator/condenserassembly without the sump 1302.

Now referring to FIG. 13E, the evaporator/condenser chamber may includea shell 1314, a plurality of tubes 1316, a lower flange 1310 and anupper flange 1312. The evaporator/condenser chamber 1304 defines aninner cavity for the condensation of high-pressure steam. Tubes 1316transfer thermal energy from the high-pressure steam to source waterwithin the tubes when the steam condenses upon the outer surface of thetubes 1316. In this embodiment the tubes 1316 may have an outer diameterof 0.75 inches and manufactured from copper. In alternate embodiments,the tubes 1316 may be manufactured from other materials including butnot limited to nickel copper or other composite materials. The diameterof the tubes 1316 may also vary depending on many variables. Seeprevious discussion in the exemplary embodiment concerning the diameterof the tubes. The length of the tubes 1316 may be determined by thelength of the inner cavity defined by the shell 1314 and the thicknessof the lower flange 1310 and upper flange 1312.

Still referring to FIG. 13E, the tubes 1316 are supported within theinner cavity defined by the shell 1314 by the lower flange 1310 andupper flange 1312, as shown on FIGS. 13B, 13C and 13E. Each flange has aplurality of apertures located axially around the center of the flange.These apertures may contain the ends of the tubes 1316. In addition, thelower flange 1310 and upper flange 1312 also secure the shell 1314 inplace and provide pathways to the sump 1302 and the mist eliminatorassembly 1306. As the source water fills the sump 1302, some waterbegins to fill the tubes 1316 located in the inner cavity of the shell1314. As thermal energy is transferred to the source water in the tubes1316, the water begins to evaporate. The source water vapor travelsthrough the tubes 1316 and into the mist eliminator assembly 1306. Thevapor enters the mist eliminator through the apertures located in theupper flange 1312.

Still referring to FIG. 13E, the shell 1314 is secured to the lowerflange 1310 and upper flange 1312 using a plurality of tie rods 1308.These tie rods are positioned outside axially around the perimeter ofthe shell 1314. In addition, the tie rods 1308 also secure the misteliminator 1306 to the upper flange 1312 and the sump 1302 to the lowerflange 1310. The length of the tie rods is governed by the length of theshell 1314 and the thickness of the lower flange 1310, upper flange1312, sump 1302 and mist eliminator 1306. The tie rods 1308 may havethreaded ends for attaching a threaded fastener onto each end of the rodsecuring the components of the evaporator/condenser together. Inaddition, the tie rods 1308 may be manufactured from any material thatis of sufficient strength, such as, stainless steel. Tie rods 1308 maybe manufactured from other materials including, but not limited tobronze, titanium, fiberglass composite materials, and carbon steel.

Still referring to FIG. 13E, in the exemplary embodiment the shell 1314is manufactured from fiberglass. Other materials may be used withpreference that those materials are corrosion resistant, have lowthermal conductivity, and sufficient structural strength to withstandthe internal pressures developed during the operation of theevaporator/condenser assembly 1300. See discussion for the exemplaryembodiment relating to the size of the inner diameter of the shell.

Still referring to FIG. 13E, the sump 1302 is connected to the lowerflange 1310 and is in fluid connection with the tubes 1316 of theevaporator/condenser assembly chamber 1304. The sump 1302 collects theincoming source water from the heat exchanger. The source water entersthe sump 1302 through an inlet port locate within the side wall of thesump. In other embodiments the inlet port may be located at a differentlocation (i.e. on the bottom). In this embodiment the sump 1302 is madefrom a composite material, G10 plastic. In other embodiments the sump1302 may be manufactured from any other material having sufficientcorrosion and high-temperatures resistant properties. Other materialsinclude but are not limited to aluminum RADEL® and stainless steel. Thesump 1302 may also include a heating element to provide thermal energyto the source water. This thermal energy assists the source water inchanging from a fluid to a vapor.

Referring now to FIGS. 14-14C, attached to the upper flange 1312 is themist eliminator assembly 1400 (also identified as 1306 of FIG. 13). Thisassembly may consist of a cap 1402, steam pipe 1404, and mist separator1406 illustrated on FIG. 14. The cap 1402 contains the low-pressuresteam that is created from the evaporator side of theevaporator/condenser. The cap 1402 may have three ports 1408, 1410, and1412 as shown FIGS. 14A-C. See discussion for the steam chest of theexemplary embodiment relating to the height of the volume for removingthe water droplets. In addition, the cap 1402 defines a cavity thatcontains the mist separator 1406 shown on FIGS. 14, 14C and 14D.

Still referring to FIGS. 14-14C, the first port 1408 may be located inthe center of the top surface of the cap 1402 and is for receiving thefirst end of the steam pipe 1404. This port allows the high-pressuresteam created by the compressor to re-enter the evaporator/condenserthrough first end of the steam pipe 1404. The steam pipe 1404 provides afluid path way for high-pressure steam to enter the evaporator/condenserthrough the mist eliminator assembly 1400 without mixing with thelow-pressure steam entering the mist eliminator assembly 1400. In thisembodiment, the steam pipe 1404 is manufactured from stainless steel. Inother embodiments the steam pipe may be manufactured from materialsincluding, but not limited to plated aluminum, RADEL®, copper-nickel andtitanium. The length of the steam pipe 1404 must be sufficient to allowfor connecting with the compressor and passing through the entire misteliminator assembly 1400. The second end of the steam pipe is receivedwithin a port located at the center of the upper flange 1312. The innerdiameter of the steam pipe 1404 may affect the pressure drop across thecompressor. Another effect on the system is that the steam pipe 1404reduces the effective volume within the mist eliminator to remove waterdroplets from the low-pressure steam.

Still referring to FIGS. 14-14C, the steam pipe 1404 also may have aplurality of exterior grooves for receiving the mist separator 1406. Themist separator 1406 is circular plate having an aperture. This apertureallows the low-pressure steam to pass through the plate. In oneembodiment a plurality of mist separators are installed within thegrooves of the steam pipe 1404. These plates would be oriented such thatthe aperture is located 180° from the preceding plate. In addition, theplate nearest to the outlet port 1410 would be orientated such that theaperture was 180° from the port. In alternate embodiments the plates mayinclude grooves on the top surface of the plates to collect waterdroplets. These grooves may be tapered to allow the collected water toflow off the plate and fall down towards the base of the mist eliminatorassembly 1400. The mist separator 1406 may be secured to the steam pipe1404 using a pair of snap rings and a wave washer.

Still referring to FIGS. 14-14C, the second port 1410 may be locatedalso in the top surface of the cap 1402 and allows the dry low-pressuresteam to exit the mist eliminator assembly 1400. See previous discussionfor the exemplary embodiment concerning the size and location of theoutlet port.

Still referring to FIGS. 14-14C, the third port 1412 may be locatedwithin the side wall of the cap 1402. This port allows water removedfrom the low-pressure steam to exit the apparatus. The location of theport is preferably at a height where the blowdown water may exit themist eliminator assembly 1400 without an excessive buildup of blowdownwater within the assembly. In addition, the height of the portpreferably is not too low, but rather preferably is sufficient tomaintain a level of blowdown water covering the outlets of the tubes. Inthe exemplary embodiment, a tube may be connected to port 1412 and theblowdown water may pass through a level sensor housing 108 and heatexchanger 102 before exiting the apparatus 100.

Still referring to FIGS. 14-14C, the mist eliminator assembly 1400 maybe manufactured from any material having sufficient corrosion and hightemperature resistant properties. In this embodiment, the misteliminator assembly is manufactured from stainless steel. The assemblymay be manufactured from other materials including but not limited toRADEL®, stainless steel, titanium, and copper-nickel.

Compressor

The water vapor distillation apparatus 100 may include a compressor 106.In the exemplary embodiment the compressor is a regenerative blower.Other types of compressors may be implemented, but for purposes of thisapplication a regenerative blower is depicted and is described withreference to the exemplary embodiment. The purpose of the regenerativeblower is to compress the low-pressure steam exiting the evaporator areaof the evaporator/condenser to create high-pressure steam. Increasingthe pressure of the steam raises the temperature of the steam. Thisincrease in temperature is desirable because when the high-pressuresteam condenses on the tubes of the condenser area of theevaporator/condenser the thermal energy is transferred to the incomingsource water. This heat transfer is important because the thermal energytransferred from the high-pressure steam supplies low-pressure steam tothe regenerative blower.

The change in pressure between the low-pressure steam and thehigh-pressure steam is governed by the desired output of product water.The output of the product water is related to the flow rate of thehigh-pressure steam. If the flow rate of steam for the high-pressuresteam from the compressor to the condenser area of theevaporator/condenser is greater than the ability of the condenser toreceive the steam then the steam may become superheated. Conversely, ifthe evaporator side of the evaporator/condenser produces more steam thanthe compressor is capable of compressing then the condenser side of theevaporator/condenser may not be operating at full capacity because ofthe limited flow-rate of high-pressure steam from the compressor.

Referring now to FIGS. 15-15G, the exemplary embodiment may include aregenerative blower assembly 1500 for compressing the low-pressure steamfrom the evaporator area of the evaporator/condenser. The regenerativeblower assembly 1500 includes an upper housing 1502 and a lower housing1504 defining an internal cavity as illustrated in FIG. 15C. See FIGS.15D-G for detail views of the upper housing 1502 and lower housing 1504.Located in the internal cavity defined by the upper housing 1502 andlower housing 1504 is an impeller assembly 1506. The housings may bemanufactured from a variety of plastics including but not limited toRYTON®, ULTEM®, or Polysulfone. Alternatively, the housings may bemanufactured from materials including but not limited to titanium,copper-nickel, and aluminum-nickel bronze. In the exemplary embodimentthe upper housing 1502 and the lower housing 1504 are manufactured fromaluminum. In alternate embodiments, other materials may be used withpreference that those materials have the properties of high-temperatureresistance, corrosion resistance, do not absorb water and havesufficient structural strength. The housings preferably is of sufficientsize to accommodate the impeller assembly and the associated internalpassageways. Furthermore, the housings preferably provide adequateclearance between the stationary housing and the rotating impeller toavoid sliding contact and prevent leakage from occurring between the twostages of the blower. In addition to the clearances, the upper housing1502 and the lower 1504 may be mirror images of one another.

Referring now to FIGS. 15D-F, the upper housing 1502 and lower housing1504 may have an inlet port 1510 and an outlet port 1512. Thelow-pressure steam from the evaporator/condenser enters the blowerassembly 1500 through the inlet port 1510. In the exemplary embodiment,the inlet port is shaped to create a spiral flow around the annular flowchannel in the upper housing 1502 and lower housing 1504. Aftercompressing the low-pressure steam, the higher-pressure steam isdischarged from the outlet port 1512. Between the inlet ports 1510 andthe outlet ports 1512 of the upper housing 1502 and lower housing 1504the clearances are reduced to prevent the mixing of the high-pressuresteam exiting the blower assembly and the low-pressure steam enteringthe assembly. The exemplary embodiment may include a stripper plate1516. At this plate the open flow channels provided in the upper housing1502 and lower housing 1504 allow only the high-pressure steam that iswithin the impeller blades to pass through to an area near the inletport 1510, called the inlet region.

Still referring to FIGS. 15D-F, the carryover of the high-pressure steamthrough the stripper plate 1516 into the inlet region may irreversiblymix with the incoming low-pressure steam entering the blower assembly1500 from the inlet port 1510. The mixing of the steam may cause anincrease in the temperature of the incoming low-pressure steam. Thehigh-pressure steam carryover may also block the incoming flow oflow-pressure steam because of the expansion of the high-pressure steamin the inlet region. The decompression duct 1514 in the upper housing1502 and lower housing 1504 extracts the compressed steam entrapped inthe impeller blades and ejects the steam into the inlet region blockingthe incoming low-pressure steam.

Still referring to FIGS. 15D-F, the distance between the inlet ports1510 and outlet ports 1512 is controlled by the size of the stripperplate 1516. In the exemplary embodiment the stripper plate area isoptimized for reducing the amount of high-pressure steam carryover intothe inlet region and maximizing the working flow channels within theupper housing 1502 and lower housing 1504.

Referring now to FIGS. 15H-K, in the exemplary embodiment the shaft 1514is supported by pressurized water fed bearings 1516 that are pressedinto the impeller assembly 1506 and are supported by the shaft 1514. Inthis embodiment, the bearings may be manufactured from graphite. Inalternate embodiments, the bearings may be manufactured from materialsincluding but not limited to Teflon composites and bronze alloys.

Still referring to FIGS. 15H-K, the water supplied to the pressurizedwater fed bearings 1516 is preferably clean water as the water may enterthe compression chamber of the blower assembly 1500. If the water entersthe compression chamber, the water will likely mix with the pure steam.Contaminated water mixing with the pure steam will result incontaminated high-pressure steam. In the exemplary embodiment productwater is supplied to the bearings.

Hydrodynamic lubrication is desired for the high-speed blower bearings1516 of the exemplary embodiment. In hydrodynamic operation, therotating bearing rides on a film of lubricant, and does not contact thestationary shaft. This mode of lubrication offers the lowestcoefficients of friction and wear is essentially non-existent sincethere is no physical contact of components.

Operating in the other lubrication regimes like Mixed Film Lubricationand Boundary Lubrication results in higher power loss and higher wearrates than hydrodynamic operation. In the exemplary embodiment theblower may operate having hydrodynamic lubrication, film lubrication ora combination of both. The running clearance between the rotatingbearing and the stationary shaft; rotating speed of the bearing; andlubricating fluid pressure and flow may affect the bearing lubricationmode.

Referring to FIGS. 15H-K, in a hydrodynamic bearing the limiting loadfactor may be affected by the thermal dissipation capabilities. Whencompared to an un-lubricated (or a boundary-lubricated) bearing, ahydrodynamic bearing has an additional mechanism for dissipating heat.The hydrodynamic bearing's most effective way to reject heat is to allowthe lubricating fluid to carry away thermal energy. In the exemplaryembodiment the bearing-feed water removes thermal energy from thebearings 1516. In this embodiment, the volume of water flowing throughthe bearing are preferably sufficient to maintain the bearing'stemperature within operational limits. In addition, diametricalclearances may be varied to control bearing feed-water flow rate,however, these clearances preferably are not large enough to create aloss of hydrodynamic pressure.

Still referring to FIGS. 15H-K, the amount of bearing-feed watersupplied to the bearings 1516 is preferably sufficient to maintainhydrodynamic lubrication. Any excess of bearing-feed water may adverselyaffect the blower assembly 1500. For example, excess water may quenchthe high-pressure steam unnecessarily reducing the thermal efficiency ofthe apparatus. Another adverse affect of excess bearing-feed water maybe power loss due to shearing of the fluid water when the excessbearing-feed water is ejected outward from the impeller assembly andforced between the housing wall and the passing impeller blades.

Referring to FIG. 15L, in the exemplary embodiment, a return path 1526for the bearing-feed water is provided within the blower to preventexcess bearing-feed water from entering the impeller buckets.

Referring back to FIGS. 15H-K, in the exemplary embodiment the bearingfeed-water pump maintains a pressure of two to five psi on the input tothe pressurized water fed bearings 1516. The bearing-feed-water flowrate may be maintained by having a constant bearing-feed-water pressure.In the exemplary embodiment, the pressure of the bearing-feed water maybe controlled to ensure the flow rate of bearing-feed water to bearings1516.

Still referring to FIGS. 15H-K, in the exemplary embodiment the impellerassembly may be driven by the motor using a magnetic drive couplingrather than a mechanical seal. The lack of mechanical seal results in nofrictional losses associated with moving parts contacting one-another.In this embodiment the magnetic drive coupling may include an innerrotor magnet 1518, a containment shell 1520, an outer magnet 1522, anddrive motor 1508.

Still referring to FIGS. 15H-K, the inner magnet rotor 1518 may beembedded within a cup. In the exemplary embodiment the magnets areaxially positioned. In other embodiments the magnets may be positionedradially. This cup may be manufactured from plastic or metallicmaterials. In some embodiments the cup material may be but is notlimited to RYTON®, ULTEM®, or polysulfone. Similarly, the magnets may bemanufactured from materials including but not limited to Ferrite,aluminum-nickel-cobalt, samarium cobalt and neodymium iron boron. In theexemplary embodiment the cup is attached to the impeller assembly 1500.In the exemplary embodiment the cup is press fit onto the shaft 1514.Other methods of attaching the cup may include but are not limited tokeyseat and setscrews.

Still referring to FIGS. 15H-K, the magnetic coupling shell 1520 ispositioned between inner rotor magnet 1518 and the outer rotor magnet1522. The magnetic coupling shell 1520 is the pressure vessel or thecontainment shell for the blower assembly 1500. This shell seals thesteam that is being compressed within the blower assembly 1500preventing the steam from escaping into the surrounding environment.

Still referring to FIGS. 15H-K, Eddy current losses may occur becausethe shell 1520 is located between the inner rotor magnet 1518 and theouter rotor magnet 1522. If the shell 1520 is electrically conductivethen the rotating magnetic field may cause electrical currents to flowthrough the shell we may cause a loss of power. Conversely, a shell 1520manufactured from a highly electrically-resistive material is preferredto reduce the amount of Eddy current loss. In the exemplary embodimenttitanium may be used for manufacturing the magnetic coupling shell 1520.This material provides a combination of high-electrical resistivity andcorrosion resistance. Corrosion resistance is preferred because of thelikelihood of contact between the bearing-feed water and the shell 1520.In other embodiments the shell 1520 may be manufactured from plasticmaterials having a higher electrical resistivity and corrosionresistance properties. In these alternate embodiments the shell 1520 maybe manufactured from material including but not limited to RYTON®,ULTEM®, polysulfone, and PEEK.

Still referring to FIGS. 15H-K, the outer rotor magnet 1522 may beconnected to a drive motor 1508. This motor rotates the outer rotormagnet 1522 causing the inner rotor magnet to rotate allowing theimpeller assembly 1506 to compress the low-pressure steam within thecavity defined by the upper housing 1502 and the lower housing 1504. Inthe exemplary embodiment the drive motor may be an electric motor. Inalternate embodiments the drive may be but is not limited to internalcombustion or Stirling engine.

Still referring to FIGS. 15H-K, the blower assembly 1500 may beconfigured as a two single-stage blower or a two-stage blower. In theoperation of a two single-stage blower the incoming low-pressure steamfrom the evaporator side of the evaporator/condenser is supplied to boththe inlet ports of the two separate stages of the blower simultaneously.The first stage may be at the bottom between the lower housing 1504 andthe impeller assembly 1506 and the second stage may be at the topbetween the upper housing 1502 and the impeller assembly 1506. As theimpeller assembly 1506 rotates, the incoming low-pressure steam from theinlet port 1510 of both stages is compressed simultaneously and thehigh-pressure steam exits from the outlet port 1512 of the upper housing1502 and the outlet port 1512 of the lower housing 1504.

Still referring to FIGS. 15H-K, in contrast the two-stage blower has twodistinct compression cycles. During the first compression cycle thelow-pressure steam from the evaporator of the evaporator/condenser issupplied to the inlet 1514 of the lower housing. The compressed steamfrom the first stage exits through the outlet port 1516 in the lowerhousing and is supplied to the inlet port 1510 of the upper housing1502. This steam compressed in the first stage is compressed againduring the second stage. After the second compression cycle the steammay exit the blower assembly 1500 through the outlet port 1512 of theupper housing 1502 at an increased pressure.

For a given blower design, both the two single-stage blower and thetwo-stage blower configurations have a unique pressure flow curves.These curves indicate that the two single-stage blower produces a higherflow rate of steam compared to the two-stage blower that produces higherpressure differential. Based on the system operating differentialpressure the flow rate and the efficiency of the blower is dependant onthe flow characteristics of the blower. Depending on the differentialpressure across the blower assembly 1500, one configuration may bepreferred over the other. In the exemplary embodiment, the blowerassembly 1500 has a two Single-stage blower configuration.

Now referring to FIGS. 16-16A, within the internal cavity defined by theupper housing 1502 and lower housing 1504 is the impeller assembly 1600(also identified as 1506 of FIG. 15). The impeller assembly 1600includes a plurality of impeller blades on each side of the impeller1602 and a spindle 1604. In the exemplary embodiment the impeller 1602may be manufactured from Radel® and the impeller spindle 1604 may bemanufactured from aluminum. In alternate embodiments these parts may bemanufactured from materials including but not limited to titanium, PPS,ULTEM®. Other materials may be used to manufacture these parts withpreference that these materials have high-temperature resistantproperties and do not absorb water. In addition, impeller spindle 1604may have passages for the return of the bearing-feed water back to thesump. These passages prevent the bearing-feed water from entering theimpeller buckets.

Still referring to FIGS. 16-16A, the blades are designed on each side ofthe impeller 1602 periphery to produce a series of helical flows as theimpeller is rotating. This flow causes the steam to repeatedly passthrough the blades for additional energy as the steam flows through theopen annular channel. The number of blades and the bucket volume may bedesigned to optimize the desired flow rate and the pressuredifferential. The number of blades and bucket volume is inverselyproportional to each other, thus increasing the number of blades createshigher pressure differential but lower flow rate. The labyrinth grooveson the outer periphery of the impeller 1602 prevents steam leakageacross the stages of the blower assembly 1500 thereby increasing theblower efficiency.

Referring back to FIGS. 15H-K, the shaft 1514 is attached to the upperhousing 1502 and lower housing 1504 and is stationary. In the exemplaryembodiment the shaft 1514 may be manufactured from titanium. In otherembodiments the shaft 1514 may be manufactured from materials includingbut not limited to aluminum oxide, silicon nitride or titanium, andstainless steel having coatings for increasing wear resistance andcorrosion resistance properties. In addition the shaft 1514 may havepassages channeling the bearing-feed water to the bearings 1516.

Still referring to FIGS. 15H-K, the blower assembly 1500 in a two-stageblower configuration may create a downward axial thrust force. Thisforce is generated because the second stage at the top of the impellerassembly 1506 is at a higher pressure compared to the first stage thatis at the bottom of the impeller assembly 1506. In an alternateembodiment, this thrust force may be balanced by an equal and oppositemagnetic force created by offsetting the inner rotor magnet 1518 and theouter rotor magnet 1522. This configuration prevents excessive wear ofthe thrust face of the lower pressurized water fed bearing 1516.

Referring now to FIGS. 17-17E, an alternate regenerative blowerembodiment 1700 is shown. This embodiment may include an impellerhousing assembly 1702, a mounting plate 1704, and a mounting flange1706. See FIGS. 17B-D for cross-section views of regenerative blowerassembly 1700. See also FIG. 17E for an exploded view of theregenerative blower assembly 1700.

Referring now to FIGS. 17-17E, the mounting plate 1704 connects themounting flange 1706 to the impeller housing assembly 1702. The mountingplate also provides ports that provide fluid pathways into the lowerhousing 1708 of the impeller housing assembly 1702 as shown on FIG. 17E.In addition, the mounting plate provides passages for the bearing-feedwater to exit the blower assembly 1700.

Now referring to FIGS. 17F-I, the impeller housing assembly 1702 mayinclude a lower housing 1708, an impeller assembly 1710, and an upperhousing 1712. Also see FIGS. 17H-I for cross-section views of theimpeller housing assembly 1702.

Referring now to FIGS. 17F-I, the lower housing 1708 and upper housing1712 define an interior cavity containing the impeller assembly 1710.This cavity provides a volume for the impeller to compress the incominglow-pressure steam. Steam may enter the impeller housing assemblythrough inlet ports located within the lower housing 1708 and the upperhousing 1712. After the low-pressure steam is compressed by the impellerassembly 1710, the high-pressure steam may exit through outlet portslocated in the lower housing 1708 and the upper housing 1712. See FIGS.17J-K for a detail view of the lower housing 1708. In addition the lowerhousing 1708 and the upper housing 1712 may be manufactured from but notlimited to aluminum, titanium, PPS, and ULTEM®.

Still referring to FIGS. 17F-I, the upper housing 1712 may include anaccess cover 1714 attached to the top surface of the housing. See FIG.17L showing a top view of the upper housing 1712 with the access cover1714 installed. This cover allows for access to the ports located withinthe upper housing cover. See FIG. 17M providing a top view of the upperhousing 1712 without the access cover 1714 installed. This viewillustrates the inlet and outlet ports located within the upper housing1712.

Referring now to FIG. 17N, the lower housing 1708 and the upper housing1712 may include a decompression duct 1716 and a strip plate 1718 on theinner surface of the housings. These features perform similar functionsas those described in the exemplary embodiment of the blower assembly1500.

Referring now to FIGS. 18-18A, the inner cavity defined by the lowerhousing 1708 and upper housing 1712 contains the impeller assembly 1800(also identified as 1710 of FIG. 17). This assembly may include aspindle 1802 and impeller having blades 1804 as shown on FIGS. 18-18A.As the low-pressure steam enters the inner cavity of the impellerhousing 1702, the impeller assembly 1800 compresses the steam as theassembly is rotated.

Still referring to FIGS. 18-18A, the drive motor provides the rotationalenergy to rotate the impeller 1804 and blades. Located between the innersurface of the spindle and the shaft may be bearings 1716. Thesebearings support the shaft and allow the impeller 1804 to rotate freely.The bearings 1716 may be located near the ends of the spindle 1802.

In alternate embodiments of the apparatus, low-pressure steam may becompressed using a liquid ring pump as described in U.S. PatentApplication Pub. No. US 2005/0016828 A1 published on Jan. 27, 2005entitled “Pressurized Vapor Cycle Liquid Distillation,” the contents ofwhich are hereby incorporated by reference herein.

Level Sensor Assembly

Referring now to FIG. 19, the exemplary embodiment of the water vapordistillation apparatus 100 may also include a level sensor assembly 1900(also identified as 108 in FIG. 1). This assembly measures the amount ofproduct and/or blowdown water produced by the apparatus 100.

Referring now to FIGS. 19-19A, the exemplary embodiment of the levelsensor assembly 1900 may include a settling tank 1902 and level sensorhousing 1904. The settling tank 1902 collects particulate carried withinthe blowdown water prior to the water entering into the blowdown levelsensor tank 1912. The tank removes particulate from the blowdown waterby reducing the velocity of the water as it flows through the tank. Thesettling tank 1902 defines an internal volume. The volume may be dividednearly in half by using a fin 1905 extending from the side wall oppositethe drain port 1908 to close proximity of the drain port 1908. This fin1905 may extend from the bottom to the top of the volume. Blowdownenters through the inlet port 1906 and must flow around the fin 1905before the water may exit through the level sensing port 1910. As theblowdown enters into the body of the vessel the velocity decreases dueto the increase in area. Any particles in the blowdown may fall out ofsuspension due to the reduction in velocity. The settling tank 1902 maybe manufactured out any material having corrosion and heat resistantproperties. In the exemplary embodiment the housing is manufactured fromRADEL®. In alternate embodiments the settling tank 1902 may bemanufactured from other materials including but note limited totitanium, copper-nickel and stainless steel.

Still referring to FIGS. 19-19A, the settling tank 1902 may have threeports an inlet 1906, a drain 1908 and a level sensor port 1910. Theinlet port 1906 may be located within the top surface of the settlingtank 1902 as shown on FIGS. 19A-B and may be adjacent to the separatingfin 1905 and opposite the drain port 1908. This port allows blowdownwater to enter the tank. The drain port 1908 may be located in thebottom of the settling tank 1902 as shown on FIGS. 19A-B. The drain port1908 provides access to the reservoir to facilitate removal ofparticulate from the tank. In the exemplary embodiment, the bottom ofthe tank may be sloped towards the drain as illustrated in FIG. 19B. Thelevel sensor port 1910 may be located within the top surface of the tankas illustrated in FIG. 19A and also adjacent to the separating fin 1905but on the opposite side as the inlet port 1906. This port provides afluid pathway to the blowdown level sensor reservoir 1912. A fourth portis not shown in FIG. 19A. This port allows blowdown water to exit thelevel sensor assembly 1900 and enter the heat exchanger. This port maybe located within one of the side walls of the upper half of thesettling tank 1902 and away from the inlet port 1906.

Still referring to FIGS. 19-19A, in the exemplary embodiment a strainermay be installed within the flow path after the blowdown water exits theblowdown level sensor reservoir 1912 and settling tank 1902. Thestrainer may collect large particulate while allowing blowdown water toflow to other apparatus components. The strainer may be manufacturedfrom material having corrosion resistant properties. In the exemplaryembodiment the strainer is manufactured from stainless steel. Inaddition, the filter element may be removable to support cleaning of theelement. The strainer removes particulate from the blowdown water tolimit the amount of particulate that enters the heat exchanger. Excessparticulate in the blowdown water may cause the inner tubes of the heatexchanger to clog with scale and sediment reducing the efficiency of theheat exchanger. In addition, particulate may produce blockage preventingthe flow of blowdown water through the heat exchanger.

Still referring to FIGS. 19-19A, the settling tank 1902 is in fluidconnection with the level sensor housing 1904. This housing may havethree interior reservoirs including but not limited to a blowdown levelsensor reservoir 1912, a product level sensor reservoir 1914, and abearing feed-water reservoir 1916. The blowdown level sensor reservoir1912 is independent of the other reservoirs to prevent contaminationfrom mixing the product water with the blowdown water. The level sensorhousing 1904 may be manufactured out any material having corrosion andheat resistant properties. In the exemplary embodiment the housing ismanufactured from RADEL®. In other embodiments the housing may bemanufactured from other materials including but not limited to titanium,copper-nickel and stainless steel. In other embodiments the housing maybe shaped differently with preference that the ball float may have arange of movement of 45 degrees and during this movement there is aconstant change in volume of the fluid level.

Still referring to FIGS. 19-19A, within the level sensor housing 1904there is a blowdown level sensor reservoir 1912. This reservoir is influid connection with the settling tank 1902 through measuring port 1910located within the top surface of the tank 1902. The reservoir providesa location where the rate of blowdown water generated by the apparatusmay be measured using a level sensor 1918. As the blowdown water fillsthe settling tank, some of that water flows through the measuring port1910 into the blowdown level sensor reservoir 1912. In addition, a ventport 1923 may be located within the top of the reservoir. This portallows air to escape the reservoir allowing blowdown water to fill thecavity. The volume of the reservoir must be sufficient to maintain alevel of water. Housings having too small volume may quickly fill anddrain adversely affecting the function of the level sensors. Incontrast, reservoirs having a large volume may have slower level sensorresponse times due to the small fluid level height changes for a givenincrease or decrease in volume. A larger volume may also dampen out theany fluctuations in the water level produced by the operation of theapparatus.

Still referring to FIGS. 19-19A, the product level sensor reservoir 1914may be located next to the blowdown level sensor reservoir 1912. Theproduct level reservoir 1914 has an inlet port 1920 and an outlet port1922. Product water enters the reservoir through the inlet port 1920 andexits the reservoir through the outlet port 1922. The outlet port 1922may be located below the low end measurement point of the level sensorto improve flow of water out of the reservoir. Similarly, the inlet port1920 may be located below the low end measurement point of the levelsensor to minimize disruption caused by the incoming water. In theexemplary embodiment the inlet port 1920 and outlet port 1922 arelocated on the side of the level sensor housing 1904 as shown in FIG.19A. This reservoir provides a space for measuring the rate of productbeing generated by the apparatus. In addition, a vent port 1923 may belocated within the top of the reservoir. This port allows air to escapethe reservoir allowing product water to fill the cavity.

Still referring to FIGS. 19-19A, the product level sensor reservoir 1914is in fluid connection with the bearing feed-water reservoir 1916. Anexternal port 1924 provides a fluid pathway for the product water toflow between the product level sensor reservoir 1914 and the bearingfeed-water reservoir 1916 shown on FIG. 19C. Product water enters thebearing feed-water reservoir 1916 through the external port 1924. Inaddition, the bearing feed-water reservoir 1916 has a supply port 1926and a return port 1928 shown on FIG. 19C. The supply port 1926 providesa fluid pathway to lubricate the bearings within the regenerative blowerassembly. Similarly, a return port 1928 provides a fluid pathway for theproduct water to return from lubricating the bearings of theregenerative blower assembly. The supply and return ports may be locatedon the side of the level sensor housing 1904 as shown in FIG. 19C.

Still referring to FIGS. 19-19A, to monitor the amount of product waterwithin the bearing feed-water reservoir 1916 an optical level sensor maybe installed. In the exemplary embodiment, the optical level sensor maybe located at approximately ⅔ height in the bearing feed-water reservoir1916. This sensor senses when water is present within the reservoirindicating that there is sufficient water to lubricate the bearings. Thesensor may be installed by threading the sensor into the level sensorhousing 1904. The sensor may include an o-ring to provide a water-tightseal. In other embodiments the sensor may be but is not limited toconductance sensor, float switches, capacitance sensors, or anultrasonic sensor.

Referring now to FIGS. 19D-F, an alternate level sensor housing 1930having two reservoirs is shown. Within the level sensor housing 1930there is a blowdown level sensor reservoir 1932. This reservoir issimilar to and performs the same function as the previously describedblowdown reservoir 1912 within the level sensor housing 1904. Incontrast, the product level sensor reservoir 1934 now contains productwater to feed the bearings of the regenerative blower. The bearingfeed-water reservoir 1916 of level sensor housing 1904 is eliminatedfrom this configuration. Instead, product water is withdrawn from theproduct level sensor reservoir to supply water for the regenerativeblower.

Still referring to FIGS. 19D-F, the product level sensor reservoir 1934may have an inlet port 1935, an outlet port 1936, a return port 1938 anda supply port 1940. The inlet port 1935 allows product water to enterthe reservoir. Similarly, the outlet port 1936 provides a fluid pathwayfor product water to leave the housing. Furthermore, the supply port1940 allows product water to leave the reservoir to lubricate thebearings of the regenerative blower. After passing through the bearingsof the regenerative blower, product water may re-enter the product levelsensor housing through the return port 1938. These ports may be locatedany where in the housing, but locating the supply port 1940 and thereturn port 1938 near the bottom of the housing may limit any adverseeffect on the function of the level sensor.

Referring now to FIGS. 19G-H, a sensor 1942 may be positioned on theoutside of the level sensor housing 1904 to receive input from the levelsensor assembly 1918. Upon receiving input from the level sensorassembly 1918 the sensor 1942 may signal that the water level in thetank is within a particular range or at a particular level. In theexemplary embodiment the sensor may be a continuous analogue sensor.This type of sensor provides continuous feedback as to the position ofthe level sensor assembly 1918. When the magnets within the levelsensors change their position, a change in voltage occurs that ismeasured and used to determine the location of the sensor. Otherembodiments may include but are not limited to a hall sensor or reedswitch. FIG. 19H illustrates one possible alternate embodiment for alevel sensor assembly including a set of float magnets 1944 and positionmagnets 1946. The position magnets 1946 are attached to the side of thelevel sensor housing 1904.

Now referring to FIGS. 20-20A, within the blowdown level sensorreservoir 1912 and the product level sensor reservoir 1914 are levelsensors 2000 (also identified as 1918 of FIGS. 19A and 19E). Thesesensors may include a base 2002, an arm 2004, and a float ball 2006.

Referring still to FIGS. 20-20A, the exemplary embodiment of the levelsensors 2000 may include a base 2002 supporting the arm 2004 and thefloat ball 2006. The assembly also includes two magnets (not shown). Thebase is connected to the arm and float ball assembly and the assemblypivots on a small diameter axial (not shown). In addition the base 2002holds two magnets. These magnets are located 180 degrees from oneanother and are located on face of the base 2002 and parallel to thepivot. In addition, there magnets may be positioned coaxially to thepivot point within the base 2002. In the exemplary embodiment themagnets may be cylinder magnets having an axial magnetization direction.

Referring still to FIGS. 20-20A, the level sensors 2000 measure therotation of the arm and ball assembly with respect to the pivot. In theexemplary embodiment, the maximum angle of displacement is 45 degrees.In this embodiment the level sensors are installed to prevent the floatball 2006 from being positioned directly below the pivot. In otherembodiments the maximum angle of displacement may be as large as 80degrees. The sensor may monitor the magnets through the wall of thehousing. This configuration allows the sensors not to be exposed tocorrosive blowdown water and to seal the level sensor housing. The basemay be manufactured from any material having corrosion resistant, heatresistant and non-magnetic properties. In the exemplary embodiment thebase 2002 is manufactured from G10 plastic. In alternate embodiments thebase 2002 may be manufactured from other materials including but notlimited to RADEL®, titanium, copper-nickel and fiberglass laminate.

Still referring to FIGS. 20-20A, attached to the base 2002 is an arm2004. The arm 2004 connects the base 2002 with the float ball 2006. Inthe exemplary embodiment the arm 2004 is manufactured of G10 plasticmaterial. Other materials may be used to manufacture the arm 2004 withpreference that those materials have sufficient high temperatureresistant properties. Other materials may include, but are not limitedto stainless steel, plastic, RADEL®, titanium, and copper-nickel. Thelength of the arm is governed by the size of the level sensorreservoirs. In addition, the exemplary embodiment has a plurality ofapertures located along and perpendicular to the arm's longitudinalaxis. These apertures reduce the weight of the arm and allow the arm tobe more sensitive to level changes.

Still referring to FIGS. 20-20A, affixed to the other end of the arm2004 is a float ball 2006. The float ball 2006 provides surface area forthe flow of water to contact. The forces applied to the float ball 2006by the water cause the level sensor assembly 2000 to pivot about thesmall diameter shaft. This change in position of the arm will indicatethe amount of water in the apparatus. The float ball may be manufacturedfrom any material having corrosion and thermal resistant properties. Inaddition, the material preferably has a low rate of water absorption. Inthe exemplary embodiment the float ball is manufactured from hollowstainless steel. For applications where the source water is highlyconcentrated, such as sea water, the float ball 2006 may be manufacturedfrom any highly corrosion resistant material including but not limitedto plastic, titanium and copper-nickel. Furthermore, the float ball 2006is preferably of the proper size to be positioned within the levelsensor housing 1904, such that the float is capable of freely moving. Inaddition, the size of the float ball 2006 is governed by the size of thelevel sensor reservoirs.

Referring now to FIGS. 21-21A, connected to the supply port 1926 of thebearing feed-water reservoir 1916 may be a bearing feed-water pump 2100(also identified as 110 on FIGS. 1-1A). The pump 2100 enables theproduct water to flow from the bearing feed-water reservoir 1916 to theregenerative blower. In the exemplary embodiment, the flow rate is 60ml/min with a pressure ranging from 2 psi to 2¼ psi. Any type of pumpmay be used with preference that the pump can supply a sufficientquantity of water to maintain the proper lubricating flow to thebearings within the regenerative blower. In addition, the pump 2100preferably is heat resistant to withstand the high temperature of thesurrounding environment and of the high-temperature product waterpassing through the pump. In the exemplary embodiment the bearingfeed-water pump 110 is a GOTEC linear positive displacement pump, modelnumber ETX-50-VIC. In alternate embodiments, other pump types such as acentrifugal pump may be used with preference that the pump is capable ofoperating in high temperatures.

Controls

The apparatus may also include a control manifold having a plurality ofcontrol valves for the different water flow paths. Typically, thismanifold may include a control valve within the inlet piping for thesource water to controls the amount of water that enters the apparatus.At excessive pressures the control valve could fail to open or once openmay fail to close thus a regulator may be included in inlet piping toregulate the pressure of the source water.

Similarly, the manifold may also include a control valve within theoutlet piping carrying blowdown water out of the apparatus. This valvemay allow the operator to control the amount of blowdown water leavingthe apparatus.

The control manifold may also include a control valve within the outletpiping for the product water. This valve may allow the operator tocontrol the amount of product water leaving the apparatus. In theexemplary embodiment, there is one control valve for each section ofoutlet piping. Similarly, the apparatus includes a vent valve to releasegaseous compounds from the evaporator/condenser. The vent valvemaintains operating conditions of the apparatus by venting off smallamounts of steam. Releasing steam prevents the apparatus fromoverheating. Similarly, releasing steam also prevents the buildup ofcompounds in the condenser space that may prevent the apparatus fromfunctioning.

Typically, the control valves may be same type. In the exemplaryembodiment, the controls are solenoid type valves Series 4BKRmanufactured from SPARTAN SCIENTIFIC, Boardman, Ohio 44513, model number9-4BKR-55723-1-002. In alternate embodiments, the controls may be butare not limited to proportional valves. The control valves areelectronically operated using an electrical input of zero to five volts.

Moreover, the apparatus may include a backpressure regulator asdescribed in U.S. Patent Application Publication No. US 2005/0194048 A1published on Sep. 8, 2005 entitled “Backpressure Regulator,” thecontents of which are hereby incorporated by reference herein.

The water vapor distillation apparatus may include a voltage regulator.Typically, the apparatus may receive single-phase power provided from atraditional wall outlet. In other countries, however, the voltage maydiffer. To account for this difference in voltage, a voltage regulatormay be included in the apparatus to ensure the proper type of voltage issupplied to the electrical components of the apparatus.

In addition, a battery may be included within the system to provideelectrical energy to the apparatus. When electrical energy is suppliedfrom a battery the apparatus will preferably include an electricalinverter to change incoming electricity from direct current toalternating current. In other embodiments, the apparatus may receiveelectrical energy from a Stirling and internal combustion engine. Theseembodiments may also require an electrical inverter. In otherembodiments, the apparatus may include a boost loop to increase theamount of voltage supplied to the apparatus to power the electricalcomponents.

Method of Distilling Water

Also disclosed herein is a method of water vapor distillation includingthe steps of straining the source water, heating the source water usinga heat exchanger, transforming the source water into low-pressure steam,removing water from the source vapor to create dry low-pressure steam,compressing the dry low-pressure steam into high-pressure steam, andcondensing the high-pressure steam into product water.

Referring now to FIGS. 22-22A, source water is contaminated water thatis transformed into a vapor and later condenses into clean and purewater called, product water. FIG. 22 illustrates the source water fluidpaths within the apparatus disclosed previously. The source water entersthe apparatus through an inlet tube connected to the heat exchanger asillustrated in FIG. 22A. Typically, a pump may be installed to cause thesource water to flow through the inlet tube into the heat exchanger.Within the inlet tube there may be a strainer 2202 installed betweenwhere the source water enters the tube and the connection with the heatexchanger, see FIG. 22A. In other embodiments, a regulator 2204 may bepositioned within the inlet tube to regulate the flow of the sourcewater into the apparatus. Similarly, in one embodiment, a valve 2206 maybe positioned within the inlet tube to isolate the apparatus from thewater source.

Referring still to FIGS. 22-22A, in operation, source water passesthrough a strainer 2202 to remove large particulates. These largeparticulates may adversely affect the operation of the apparatus, byclogging the inlet and blowdown valves or the inner tubes of the heatexchanger. In addition, particulate may be deposited onto the tubes ofthe evaporator/condenser reducing the efficiency of the apparatus. Inthe exemplary embodiment the strainer 2202 is located before the controlvalves. In other embodiments the strainer may be positioned before theinlet pump (not shown). In the exemplary embodiment the strainer 2202has a 50 micron user-cleaner unit. In alternate embodiments theapparatus may not include a strainer 2202. After the source water passesthrough the strainer 2202, the water enters the heat exchanger 2208.

Referring now to FIG. 22B, upon entering the heat exchanger 2208, thesource water may fill the outer tube of the heat exchanger 2208. In theexemplary embodiment, the heat exchanger is a counter-flow tube-in-tubeheat exchanger. The source water enters the heat exchanger atapproximately ambient temperature. Conversely, the product and blowdownwater enter the heat exchanger having temperature greater than ambient.The source water enters the heat exchanger at one end and the productand blowdown water enter the heat exchanger at the opposite end. As thesource water flows through the heat exchanger the high thermal energy ofthe product and blowdown water is conducted outwardly from the innertubes of the heat exchanger to the source water. This increase in thetemperature of the source water enables the water to more efficientlychange into steam in the evaporator/condenser.

Referring now to FIGS. 22C-D, once the source water passes through thecounter-flow tube-in-tube heat exchanger, the water exits the heatexchanger and enters the regenerative blower motor cooling loop. Duringoperation, the regenerative blower motor 2210 creates thermal energy.This thermal energy must be removed from blower motor 2210 for theblower to operate properly. As the source water passes through theblower motor cooling loop the thermal energy created by the blower motoris transferred to the source water. The heat transfer allows the blowermotor to maintain a lower operating temperature and raises thetemperature of the source water. The higher temperature of the sourcewater increases the efficiency of the apparatus, because less energy isrequired to produce the phase change of the source water to a vapor. Thesource water leaves the regenerative blower motor cooling loop entersthe evaporator/condenser through the sump 2212, illustrated in FIG. 22E.

Referring now to FIGS. 23-23A, also present in the apparatus is highlyconcentrated source water, called blowdown water. This water removesparticulate from the apparatus to prevent scaling on the tubes of theevaporator/condenser. This fluid may contain any non-volatilecontaminants that were present in the source water. These contaminantsmay include but are not limited to be scale from foulants, heavy metalsor organic compounds. Specifically, these foulants may include but notlimited to calcium carbonate, magnesium carbonate In addition, blowdownwater transfers thermal energy to the source water when passing throughthe heat exchanger. FIG. 23 shows the blowdown water fluid paths withinthe apparatus disclosed previously. The blowdown water is collected inthe steam chest 2302 as shown in FIG. 23A. As the low-pressure watervapor passes through the steam chest 2302, water droplets are separatedfrom the water vapor. These droplets accumulate in the bottom of thesteam chest 2302 and are added to the existing blowdown water. As thelevel of blowdown water increases, the water exits the steam chest 2302through a port. Through this port, the blowdown water leaves the steamchest 2302 and enters the level sensor housing 2304, illustrated in FIG.23A.

Referring now to FIGS. 23B-C, the blowdown water enters the level sensorhousing 2304 and fills the settling tank 2306. As the blowdown waterpasses through the settling tank 2306 particulate within the watersettles to the bottom of the tank and thus separating the water from theparticulate. Separating the particulate from the water prevents theparticulate from entering the heat exchanger. The heat exchanger may beadversely affected by the presence of particulate in the water.Particulate may collect in the inner tubes of the heat exchanger causingthe heat exchanger to have a lower efficiency. Particulate may reduceflow of blowdown through the inner tubes reducing the amount of thermalenergy capable of being transferred to the source water. In someinstances, the collection of particulate may produce a blockage withinthe inner tubes preventing the flow of blowdown water through the heatexchanger. As blowdown water fills the settling tank 2306, the water mayalso fill the blowdown level sensor reservoir 2308, illustrated in FIG.23C.

Referring now to FIGS. 23D-G, upon exiting the level sensor housing2304, the blowdown water may pass through a strainer 2310 beforeentering the heat exchanger 2312 shown on FIG. 23E. The strainer 2310removes particulates within the blowdown water that remain after flowingthrough the settling tank 2306 of the level sensor housing 2304.Removing particulates from the blowdown water reduces particulatebuild-up in the heat exchanger and valves within the system. The blowdown water enters the heat exchanger 2312 fills one of the inner tubesas shown in FIG. 23E. The water fills the heat exchanger 2312 as shownin FIG. 23F. As the blowdown water passes through the heat exchanger,thermal energy is conducted from the higher temperature blowdown waterto the lower temperature source water through the tube containing theblowdown water. The blowdown water exits the heat exchanger illustratedon FIG. 23G. After leaving the heat exchanger, blowdown fluid may passthrough a mixing can 2314 to prevent steam being released from theapparatus potentially harming a person or adjacent object. Steam may beperiodically vented from the condenser space to maintain the apparatusenergy balance. Similarly, gaseous vapors (ex. volatile organiccompounds, air) must be purged from the condenser space to maintainproper operation of the apparatus. Both the steam and gaseous vapors arereleased into the mixing can 2314 having low-temperature blowdown water.By mixing the steam into the blowdown water the steam condenses allowingfor steam to be released safely. In other embodiments, there may be avalve positioned in the tubing connecting the heat exchanger 2312 andmixing can 2314 to isolate the mixing can from the apparatus or adjustthe flow rate of the blowdown water exiting the apparatus.

Referring now to FIGS. 24-24A, product water is formed whenhigh-pressure steam condenses when contacting the outer surface of thetubes within the evaporator/condenser. FIG. 24 shows the product waterfluid paths within the apparatus disclosed previously. The product wateris created in the evaporator/condenser 2402 as shown in FIG. 24A. As thehigh-pressure steam condenses against the outer surface of the tubes ofthe evaporator/condenser forming water droplets. These dropletsaccumulate in the bottom of the evaporator/condenser 2402 creatingproduct water. As the level of product water increases, the water exitsthe evaporator/condenser 2402 through a port and enters the level sensorhousing 2404, illustrated in FIG. 24A.

Referring now to FIGS. 24B-24E, the product water may enter the levelsensor housing 2404 through a port connected to the product level sensorreservoir 2406 shown on FIG. 24B. This reservoir collects incomingproduct water and measures the amount of water created by the apparatus.The water exits the product level sensor reservoir 2406 and enters theheat exchanger 2408 illustrated in FIG. 24C. While passing through theheat exchanger 2408, the high-temperature product water transfersthermal energy to the low-temperature source water through the innertubes of the heat exchanger 2408. FIG. 24D illustrates the product waterpassing through the heat exchanger 2408. After passing through the heatexchanger 2408, the product water exits the apparatus as illustrated inFIG. 24E. In the exemplary embodiment the apparatus may include aproduct-divert valve 2410 and product valve 2412. The product valve 2412allows the operator to adjust the flow rate of product water leaving theapparatus. Typically, the once the reservoir is 50 percent full, thenthe product valve 2412 is cycled such that the amount of water enteringthe reservoir is equal to the amount leaving the reservoir. Duringinitial start-up of the system the first several minutes of productionthe product water produced is rejected as waste by opening theproduct-divert valve 2410. Once it has been determined that the productis of sufficient quality the product-divert valve 2410 closes and theproduct valve 2412 begins operation.

Referring now to FIGS. 24F-24H, as product water fills the product levelsensor reservoir 2406, water may also enter the bearing feed-waterreservoir 2410. The bearing feed-water reservoir 2410 collects incomingproduct water for lubricating the bearings within the regenerativeblower 2412. Product water exits the bearing feed-water tank 2410 andmay enter a pump 2414 as shown in FIG. 24G. The pump 2414 moves theproduct water to the regenerative blower. After leaving the pump 2414,the product water enters the regenerative blower 2412 illustrated onFIG. 24H.

Referring now to FIGS. 24H-24I, upon entering the blower 2412, theproduct water provides lubrication between the bearings and the shaft ofthe blower. After exiting the regenerative blower 2412, the productwater may re-enter the level sensor housing 2404 through the bearingfeed-water reservoir 2410, see FIG. 24I.

Now referring to FIGS. 25-25C, to support the flow of the waterthroughout the apparatus vent paths may be provided. These paths supportthe flow of the water through the apparatus by removing air or steamfrom the apparatus. The vent paths are shown in FIG. 25. FIG. 25Aillustrates a vent path from the blowdown level sensor reservoir 2502 tothe steam chest 2504 of the evaporator/condenser 2508. This path allowsair within the reservoir to exit allowing more blowdown water to enterthe reservoir. Similarly, FIG. 25B illustrates a vent path from theproduct level sensor reservoir 2506 to the evaporator/condenser 2508.This path allows air within the reservoir to exit allowing product waterto enter the reservoir. Finally, FIG. 25C shows a vent path from thecondenser area of the evaporator/condenser 2508 to allow air within theapparatus to exit the apparatus to the surrounding atmosphere through amixing can 2510. In addition, this vent path assists with maintainingthe apparatus' equilibrium by venting small quantities of steam from theapparatus.

Referring now to FIG. 26, in operation, source water enters the sump2602 of the evaporator/condenser 2608 in the manner described in FIGS.22-22E. When source water initially enters the sump 2602, additionalthermal energy may be transferred to the water using a heating element.Typically, the heating element may be used during initial start up ofthe water vapor distillation apparatus. Otherwise the heater will nottypically be used. As the amount of source water in the sump increases,the water flows out of the sump and into the tubes 2604 of theevaporator/condenser through ports within a plate 2606 positionedbetween the sump 2602 and the evaporator/condenser 2608, illustrated inFIG. 26. During initial start-up of the apparatus, the evaporatorsection of the evaporator/condenser 2608 is flooded with source wateruntil there is sufficient amount of water in the blowdown level sensorreservoir. After initial start-up the tubes 2604 remain full of sourcewater.

Referring now to FIGS. 26A-26E, once in the tubes 2604, the source wateris heated from conduction of thermal energy through the tube walls fromthe high-pressure steam present on the outside of the tubes 2604. FIG.26A illustrates the wet low-pressure steam flowing through the tubes2604 of the evaporator/condenser 2608. The wet low-pressure steamtravels through the tubes 2604 of the evaporator/condenser 2608 andenters the steam chest 2610 illustrated in FIG. 26B. As steam flowsthrough the interior of the steam chest 2610, the water droplet withinthe steam are separated from the steam. These droplets collect at thebase of the steam chest 2610 and are added to the blowdown water alreadypresent in the base, see FIGS. 26C-D. Blowdown water flows out of theapparatus in manner described in FIGS. 23-23G. The dry low-pressuresteam exits the steam chest 2610 and enters the regenerative blower 2612as shown on FIGS. 26E-F.

Now referring to FIGS. 26F-H, once in the regenerative blower 2612, thedry low-pressure steam is compressed creating dry high-pressure steam.After the dry steam is compressed, the high-pressure steam exits theregenerative blower 2612 and enters the steam tube 2614 of the steamchest 2610. See FIGS. 26G-H illustrating the steam exiting the blower2612 and entering the steam tube 2614 of the steam chest 2610.

Now referring to FIGS. 26H-J, the steam tube 2614 is in fluid connectionwith the inner cavity of the evaporator/condenser 2608. The steam tube2614 provides an isolated pathway for the steam to enter the condenserside of the evaporator/condenser 2608 from the blower 2612. Thehigh-pressure steam is isolated to maintain the pressure of the steamand to ensure that the steam has no contaminants. The dry high-pressuresteam exits the steam tube 2614 of the steam chest 2610 and enters theinner cavity of the evaporator/condenser 2608. See FIG. 26I showing theinner cavity of the evaporator/condenser 2608 containing high-pressuresteam. As the high-pressure steam contacts the outer surfaces tubes 2604of the evaporator/condenser 2608, the steam transfers thermal energy tothe tubes 2604. This energy is conducted through the tube walls to thesource water located within the tubes 2604. When the energy istransferred from the steam to the tube walls, the steam condenses from avapor to a fluid. This fluid is known as product water. As waterdroplets form on the outside of the tube walls, these droplets flow downto the base of the evaporator/condenser 2608. See FIG. 26J showing theformation of product water within the inner cavity of theevaporator/condenser 2608. When the amount of product water within thecavity is sufficient, product water may flow out of theevaporator/condenser as illustrated in FIGS. 24-24I.

Referring now to FIG. 27, there are several factors that may affect theperformance of the apparatus described. One of these factors is pressuredifference across the regenerative blower. FIG. 27 is a chartillustrating the relationship between the amount energy required toproduce one liter of product water and the change in pressure across theregenerative blower. Ideally, one would want to operate the blower, suchthat, the most product water is produce using the least amountelectricity. From this graph, operating the blower with a pressuredifferential between 1.5 psi and 2 psi produces a liter of product waterusing the least amount of energy. Operating the blower at pressuresabove or below this range increases the amount of energy that is neededto produce one liter of water.

Now referring to FIG. 28, another factor that may affect the performanceof the apparatus is the number of heat transfer tubes installed withinthe inner cavity of the evaporator/condenser assembly. FIG. 28illustrates the relationship between the number of heat transfer tubesand the rate of production of product water for a given change inpressure across the regenerative blower. From this chart, it isdetermined that having a greater number of heat transfer tubes increasesthe production of product water. In this graph, the configurationproducing the largest amount of product water per hour is the assemblyhaving 85 tubes. The configuration producing the least amount of wateris the assembly having only 43 tubes for pressures below 2 psi.

Referring now to FIG. 29, this figure illustrates the amount of productwater created by different heat transfer tube configurations. In thisgraph, the configuration having 102 heat transfer tubes generated thehighest amount of product water. In contrast, the configuration having ashorter tube length and only 48 tubes produced the least amount ofproduct water.

Now referring to FIG. 30, despite having a lower number of tubes thanother configurations, the 48 heat transfer tube configuration producesmore water per surface area. FIG. 30 illustrates the relationshipbetween the amount of product created and the size of the heat transfersurface area. This chart shows that the 48 heat transfer tubeconfiguration having a tube length of 15 inches is the most efficientdesign. The least efficient configuration is the 102 heat transfer tubedesign. Thus, having a large number of tubes within theevaporator/condenser may produce more water, but a design having a lowernumber of tubes may provide the most efficient use of resources.

Referring now to FIG. 31, this figure illustrates the difference of theperformance two 48 heat transfer tube designs. In this chart thedifference in the designs is the tube lengths. At various pressurechanges across the regenerative blower, this graph contrasts the amountof energy used and rate of production of water for the twoconfigurations. The configuration having the 20 inch long tubes producesslightly more product while consuming slightly less energy at equalpressure differences across the regenerative blower.

Methods of Control

The pressure difference across the compressor directly determines theamount of product water that the apparatus may generate. To ensure aparticular amount of product water output from the apparatus, one canadjust the pressure difference across the compressor. Increasing thespeed of the compressor will typically result in an increase in pressuredifferential across the two sides of the evaporator/condenser.Increasing the pressure differential increases rate at which sourcewater is evaporated into clean product water.

One of the limiting factors in controlling the water vapor distillationapparatus 100 is the amount of blowdown water that is required tooperate the machine. Without sufficient blowdown water, particulateseparated from the source water will remain in the apparatus. Thisbuild-up of particulate will adversely affect the operation andefficiency of the apparatus.

To ensure that particulate is removed from the apparatus, there must bea sufficient amount of blowdown water present to carry the particulateout of the apparatus. To determine how much blowdown water is requiredto operate the apparatus in a particular environment, one must know thequality of the water entering the apparatus (source water). If thesource water has a high concentration of particulate then more blowdownwater will be needed to absorb and remove the particulate from theapparatus. Conversely, if the source water has a low concentration ofparticulate then less blowdown water will be required.

To control and observe the amount of product and blowdown watergenerated by the apparatus a couple of different control methods may beimplemented. These schemes may include but are not limited to measuringthe level of product and blowdown water within reservoirs located in theapparatus, measuring the flow rate of the product and blowdown watercreated by the apparatus, measuring the quality of the incoming sourcewater and measuring the output quality of the product water.

The level sensor assembly of the exemplary embodiment may measure boththe level of and the flow rate of water. The water level may be measuredby the movement of the level sensor assembly. As the water fills thereservoir, the water produces a change in position of the level sensorassembly.

One may determine the flow rate of water by knowing the change inposition of the level sensor assembly, the area of the reservoir and thetime associated with the change in water level. Using a float sensor todetermine flow is advantageous because there is no pressure dropresulting from the use of a float sensor. The flow rate may indicate theperformance of the apparatus and whether that performance is consistentwith normal operation of the apparatus. This information allows theoperator to determine whether the apparatus is functionally properly.For example, if the operator determines the flow rate is below normaloperating conditions, then the operator may check the strainer withinthe inlet piping for impurities or the tubes of the evaporator/condenserfor scaling. Similarly, the operator may use the flow rate to makeadjustments to the apparatus. These adjustments may include changing theamount of blowdown and product water created. Although a flow rate mayindicate performance of the apparatus, this measurement is not required.

The water quality of either the inlet source water or the outlet productwater may be used to control the operation of the water vapordistillation apparatus. This control method determines the operation ofthe machine based on the quality of the water. In one embodiment theconductivity of the product water is monitored. When the conductivityexceeds a specified limit than the sensor sends a signal to shut downthe apparatus. In some embodiments the sensors may be, but are notlimited to a conductivity sensor. In an alternate embodiment, mayinclude monitoring the conductivity of the blowdown water. When theconductivity of the blowdown water exceeds a specified limit then thesensor sends a signal to increase the amount of source water enteringthe apparatus. The increase in source water will reduce the conductivityof the blowdown water. In another embodiment, the conductivity of thesource water may be monitored. When the conductivity exceeds a specifiedlimit than the sensor sends a signal to adjust the flow rate of thesource water. The higher the source water conductivity may result inhigher flow rates for the source and blowdown water.

In alternate embodiments, the apparatus may include a control schemewhere the apparatus has a steady-state mode. During this mode, theapparatus reduces the amount of power consumed. In other embodiments,the heating elements may remain operating during this mode to maintain aparticular temperature or temperature range of the source water in thesump. Maintaining the temperature of the source water in the sumpreduces the amount of time for the machine to start generating moreproduct water. In addition, during this mode the regenerative blower isnot functioning and the inlet and outlet valves are closed.

Examples of tests that may be performed on a source water sample toanalyze the quality of the source water include, but are not limited to,bacterial testing, mineral testing, and chemical testing. Bacterialtests indicate the amount of bacteria that may be present within thesample. The most common type of bacterial test is total coliform.

Mineral testing results may indicate the amount of mineral impurities inthe water. Large amounts of minerals and other impurities may pose ahealth hazard and affect the appearance and usefulness of the water.

Another type of water testing that may be accomplished is chemicaltesting. Many man-made chemicals may contaminate a water supply and posehealth hazards to potential consumers of the water. Unless a specificchemical or type of chemical is suspected to be in the water, this typeof test may not be routinely performed as the testing is expensive forunspecified chemical contaminants. However, if a particular chemical issuspected to be present in the source water, a test may be performed.Examples of some specific water quality tests are described below.

pH—measures the relative acidity of the water. A pH level of 7.0 isconsidered neutral. Pure water has a pH of 7.0. Water with a pH levelless than 7.0 is considered to be acidic. The lower the pH, the moreacidic the water. Water with a pH greater than 7.0 is considered to bebasic or alkaline. The greater the pH, the greater its alkalinity. Inthe US, the pH of natural water is usually between 6.5 and 8.5. Freshwater sources with a pH below 5 or above 9.5 may not be able to sustainplant or animal species. pH may be determined using any known method inthe art for testing.

The pH is preferably measured immediately at the source water test siteas changes in temperature affect pH value. Preferably, the water sampleis taken at the source at a location away from the “bank”, if using alake, stream, river, puddle, etc, and below the water surface.

Nitrate—Nitrogen is an element required by all living plants and animalsto build protein. In aquatic ecosystems, nitrogen is present in manyforms. It may combine with oxygen to form a compound called nitrate.Nitrates may come from fertilizers, sewage, and industrial waste. Theymay cause eutrophication of lakes or ponds. Eutrophication occurs whennutrients (such as nitrates and phosphates) are added to a body ofwater. These nutrients usually come from runoff from farmlands andlawns, sewage, detergents, animal wastes, and leaking septic systems.The presence of nitrate may be determined using any known method in theart for testing

Turbidity—Turbidity refers to how clear or how cloudy the water is.Clear water has a low turbidity level and cloudy or muddy water has ahigh turbidity level. High levels of turbidity may be caused bysuspended particles in the water such as soil, sediments, sewage, andplankton. Soil may enter the water by erosion or runoff from nearbylands. Sediments may be stirred up by too much activity in the water,for example, by fish or humans. Sewage is a result of waste dischargeand high levels of plankton may be due to excessive nutrients in thewater.

Where the turbidity of the water is high, there will be many suspendedparticles in it. These solid particles will block sunlight and preventaquatic plants from getting the sunlight they need for photosynthesis.The plants will produce less oxygen thereby decreasing the DO levels.The plants will die more easily and be decomposed by bacteria in thewater, which will reduce the DO levels even further. Turbidity may bedetermined using any known method in the art for testing

Coliform—Where coliform bacteria are present in the water supply it isan indication that the water supply may be contaminated with sewage orother decomposing waste. Usually coliform bacteria are found in greaterabundance on the surface film of the water or in the sediments on thebottom.

Fecal coliform, found in the lower intestines of humans and otherwarm-blooded animals, is one type of coliform bacteria. The presence offecal coliform in a water supply is a good indication that sewage haspolluted the water. Testing may be done for fecal coliform specificallyor for total coliform bacteria which includes all coliform bacteriastrains and may indicate fecal contamination. The presence of coliformmay be determined using any known method in the art for testing.

In operation the water machine may perform conductivity testing of thesource water and/or the product water to determine the quality of thewater entering and exiting the system. This testing may be accomplishedusing conductivity sensors installed within the inlet and outlet pipingof the system. Water having a high conductivity indicates that the waterhas greater amount of impurities. Conversely, water having a loweramount of conductivity indicates that water has a lower level ofimpurities. This type of testing is generic and provides only a generalindication of the purity/quality of the water being analyzed.

Other types of testing may be accomplished for analyzing specific levelsof the following water impurities/characteristics include but are notlimited to pH, hardness, chlorides, color, turbidity, sulfate, chlorine,nitrites nitrates, and coliforms. Typically to analyze the waterentering or exiting the machine the operator may first obtain a sampleof the water. After obtaining the desired sample the water may then betested using a water testing kit available from Hach Company, Loveland,Colo. 80539-0389. Other methods of testing the purity of water mayinclude sending the water to laboratory for analysis.

Systems for Distilling Water

Also disclosed herein is where the apparatus for distilling waterdescribed previously may be implemented into a distribution system asdescribed in U.S. Patent Application Pub. No. US 2007/0112530 AIpublished on May 17, 2007 entitled “Systems and Methods for DistributedUtilities,” the contents of which are hereby incorporated by referenceherein. Furthermore, a monitoring and/or communications system may alsobe included within the distribution system as described in U.S. PatentApplication Pub. No. US 2007/0112530 A1 published on May 17, 2007entitled “Systems and Methods for Distributed Utilities,” the contentsof which are hereby incorporated by reference herein.

Alternate Embodiments

Although the exemplary embodiment of the still/water vapor distillationapparatus has been described, alternate embodiments of still, includingalternate embodiments of particular elements of the still (i.e., heatexchanger, evaporator condenser, compressor, etc) are contemplated.Thus, in some alternate embodiments, one of more of the elements arereplaced with alternate embodiment elements described herein. In someembodiments, the entire still is replaced by an alternate embodiment,for example, the system as described in one embodiment utilizes theexemplary embodiment as the still while in other embodiments, the systemutilizes an alternate embodiment.

Referring to FIGS. 32-32C, alternate embodiments of the water vapordistillation apparatus having a liquid ring pump 3200 disclosed. Thering pump may include a fully rotatable housing that provides maximumreduction in frictional loss yet maintains simplicity of design andcost-effectiveness of production is shown in FIGS. 32 through 32C. Ascan be seen in FIG. 32, stator 3202 is stationary relative to rotor3204, and comprises an intake 3206 and exit 3208. Steam is drawn in atpressure P₁ and passes into rotor chamber 3210. Rotor 3204 is off-setfrom a central axis Z upon which the rotating housing and the liquidring pump are centered. As rotor 3204 turns about central shaft 3212with rotor bearings 3214, the effective volume of chamber 3210decreases. Steam is thereby compressed to pressure P₂ as it is carriedalong a rotational path into exit 3208, to be routed to anevaporator/condenser 104 of FIG. 1. Preferably, a rotatable housing (notshown) rotates with the liquid ring in the liquid ring pump, to reduceenergy loss due to friction.

Referring to FIGS. 32A-B, the stator 3202 has support structures 3216 inthe input and output regions. The individual vanes 3218 of rotor 3204can be seen below the support structures 3216 in the top view of stator3202 shown in FIGS. 32A-B, as well as the concentric placement of rotor3204 about the central axis. This particular embodiment of a liquid ringpump is both axially fed and axially ported and may have a vertical,horizontal, or other orientation during operation. FIG. 32C shows yetanother view of this embodiment.

The liquid ring pump 3200 is designed to operate within a fairly narrowrange of input and output pressure, such that generally, the apparatusoperates in the range of from 5 to 15 psig. Apparatus pressure may beregulated using check valves to release steam from chamber 3210 of FIGS.32-32C. Improved apparatus performance is preferably achieved by placingexit 3208 of the exhaust port at a specific angle of rotation about therotor axis, wherein the specific angle corresponds to the pressure risedesired for still operation. One embodiment of a specific port openingangle to regulate apparatus pressure is shown in FIG. 32A. Exit 3208 isplaced at approximately 90 degrees of rotation about the rotor access,allowing steam from chamber 3210 to vent. Placing exit 3208 at a highangle of rotation about the stator axis would raise the apparatuspressure and lower pump throughput, while placing exit 3208 at a lowerangle of rotation about the stator axis would result in lower apparatuspressure and increased pump throughput. Choosing the placement of exit3208 to optimize apparatus pressure may yield improved pump efficiency.Further, the placement of exit 3208 to maintain apparatus pressure mayminimize apparatus complexity by eliminating check valves at the exhaustports to chamber 3210, thereby providing a simpler, more cost-effectivecompressor.

Referring now to FIG. 32D, during operation, it may be desirable tomeasure the depth of the liquid ring in the compressor, to optimizeperformance. In the embodiments herein disclosed, liquid ring pumphousing 3232 rotates with the liquid ring in the pump, and thetemperature of the fluid is typically around 110 degrees C. Methods ofmeasuring ring depth include any one of the usual methods, such as usingultra-sound, radar, floats, fluid conductivity, and optical sensors.Because of the complexities of the rotating housing, use of a capacitivesensor is a preferred embodiment for this measurement, wherein as thedepth of the fluid in the capacitor changes, the capacitance of thecapacitor also changes.

Still referring to FIG. 32D, a disc-shaped capacitor sensor plate 3234is mounted to the bottom of rotating housing 3232, equidistant from thebottom surface 3232A of rotating housing 3232, and the bottom surface3204A of rotor 3204. The capacitor is thus defined by housing 3232,rotor 3204, and capacitor sensor 3234. Leads 3240 connect the capacitor,from capacitor sensor 3234, through a passageway 3236A in rotatinghousing shaft 3236, to the secondary 3242 of a core transformer,preferably of ferrite (not shown). In one embodiment, the secondary 3242is rotating at the same speed as the capacitor plate, and is ininductive communication with the primary of the ferrite coretransformer. The primary winding 3238 is stationary, and signals to andfrom the level-measuring capacitor are communicated through thetransformer, in this way enabling depth information to be transmittedfrom a rotating position to a stationary position. Capacitance ismeasure by determining the LC resonance of the capacitor (C) with theinductance (L) of the transformer secondary. In an exemplary embodiment,an LC oscillator circuit is constructed and the oscillation frequency isused as a measure of the capacitance.

Referring to FIG. 32E, this figure illustrates an alternate design ofthe pump 3200 to prevent contaminated fluid droplets from beingentrained and carried along with vapor to evaporator/condenser 104 ofFIG. 1. In such an embodiment, the liquid ring pump 3200 is within thehead space of the evaporator/condenser 104, and mist is eliminated asrotating housing 3232 rotates, wherein the rotation creates a cycloneeffect, flinging mist and water droplets off by centrifugal force tocollide with the still housing and run down to the water in the sump.There may also be fins 3244 extending from the outside of rotatinghousing 3232 to enhance circulation and rotation of vapor in the annularspace between rotating housing 3232 and fixed housing 3228. A steam exit3242 is provided for passage of steam to evaporator/condenser 104.

Referring now to FIGS. 32F-G, an alternative embodiment for a liquidring pump 3200 may include a ring pump 3252 with an outer rotatablehousing 3254 that encloses a single two-channel stator/body 3256, and arotor 3258, wherein the seal surface between the rotatable housing 3254and stationary stator/body 3256 is a cylinder. Two-channel stator/body3256 is kept stationary in reference to a chamber 3260 of pump 3252 aswell as to rotor 3258 and rotatable housing 3254, and comprises anintake 3262 and an exit 3264. Steam is drawn in at pressure P₁ andpasses through an intake orifice 3266. When the intake orifice 3266lines up with an intake hole 3268 in rotor 3258 as the rotor spinsaround stationary stator 3256, the steam passes through intake hole 3268into a rotor chamber 3270. Rotor 3258 is offset from a central axis Z sothat, as rotor 3258 turns, the effective volume of rotor chamber 3270decreases. In this way, steam is compressed to pressure P₂ as it iscarried along a rotational path to an exit hole 3272 in rotor 3258. Asrotor 3258 turns, exit hole 2 lines up with an exit orifice 3274 ofstationary exit 3264, and the steam at pressure P₂ passes through exitorifice 3274 into exit 3264 to be routed to the evaporator/condenser. Insuch an embodiment, rotatable housing 3254 rotates with water 3276present in chamber 3260 thereby reducing frictional energy losses due towindage. There may also be a small hole 3278 present in the housing 3254to permit water 3276 to leave and/or enter chamber 3260, therebycontrolling the fluid level in the pump. In addition, rotor 3258 hasmultiple vanes 3280 that are readily apparent when rotor 3258 is viewedfrom above, as in FIG. 32G. Individual rotor chamber 3270, andindividual intake hole 3268 and exit hole 3272 for each rotor chamber3270, are also easily seen in this view.

Referring to FIG. 32H, Another alternative embodiment of a liquid ringpump, wherein the interface between rotatable housing 3254 and stator3256 is conical rather than cylindrical. In this embodiment, a rotordrive shaft 3282 has an end 3286 situated upon a bearing 3284 thatallows rotatable rotor housing 3254 to rotate with rotor 3258. Intake3262 and exit 3264, with corresponding intake orifice 3266 and exitorifice 3274, are kept stationary with respect to rotor 3258 and rotorhousing 3254.

Referring now to FIGS. 32F, H and I, other further embodiments mayinclude either a conical or axial seal 3282 present between stationarysections 3264 and 3262 and rotor 3258. In the conical embodiment seenmost clearly in FIG. 32I, seal 3282 thereby separates intake orifice3266 from exit orifice 3274 of rotor 3258 to prevent leaks. The liquidring pumps shown in FIGS. 32E-I and 7 are both axially fed and radiallyported, in contrast with the embodiment of a liquid ring pump, discussedwith reference to FIGS. 32-32C (vide supra), which is axially fed andaxially ported.

In alternate embodiments, the water vapor distillation apparatus mayinclude a backpressure regulator. Backpressure regulators may assistwith maintaining the safe and optimal operation of processes conductedunder pressure. In operation the water vapor distillation apparatus mayinclude a backpressure regulator to purify brackish or sea water intodrinking water, excess apparatus pressure from start-up volatilecomponents, or created from compressors running off-specification, mayconstitute a danger to operators if such pressure is not relieved in asafe manner. As well, volatile components present in feed streams atstart-up may present contaminants that interfere with proper operationof the apparatus. Backpressure regulators may serve to relieve excesspressure, and to return an operating apparatus to a desired operatingpressure.

The water vapor distillation apparatus embodiments described previouslygenerally operate above atmospheric pressure, typically around 10 psig.Such an apparatus advantageously provides higher steam density at thehigher pressure, thereby allowing more steam to be pumped through apositive displacement pump than at lower pressure. The resulting higherthroughput provides overall improved system efficiency. Further, thehigher throughput and higher system pressure reduces the power neededfor compressor, and eliminates the need for two additional pumps—one forpumping condensed product and another for pumping blowdown stream.Overall construction is simplified, as many shapes withstand internalpressure better than external pressure. Importantly, operating atsuper-atmospheric pressure reduces the impact of minor leaks on theoverall efficiency and performance. Non-condensable gases such as airinhibit the condensation process, and would be magnified atsub-atmospheric pressure, where minor leaks would serve to suck in air,something which will not occur in a system operating atsuper-atmospheric pressure.

Referring now to FIGS. 33 and 33A, these figures depict views of abackpressure regulator that may be incorporated into the water vapordistillation apparatus 100 when operating the apparatus aboveatmospheric pressure. The backpressure regulator 3300 has a vessel 3302containing an orifice 3304. One side of the orifice is connected to apressurized conduit of an apparatus (e.g., the outlet of a compressor ina vapor compression distillation apparatus) which may be exposed to thefluctuating elevated pressure. The other side of the orifice terminatesin a port 3306. The port 3306 is covered by a movable stop 3308, in theshape of a ball. The stop 3308 is retained to an arm 3310 by means of aretainer 3312 at a fixed distance from a pivot pin 3314. The arm 3310 isattached by a hinge via the pivot pin 3314 to a point with a fixedrelation to the orifice port 3306. The arm 3310 includes a counter mass3316 suspended from the arm that is movable along an axis 3318 such thatthe distance between the counter mass 3316 and the pivot pin 3314 may bevaried. In the embodiment shown in FIG. 33, the axial direction of theorifice 3304 is perpendicular to the direction of the gravitationalvector 3320. The backpressure regulator may also include a housing,which prevents foreign matter from entering the regulator andinterfering with the function of the internal components.

Still referring to FIGS. 33 and 33A, in operation the arm 3310 maintainsa horizontal position with respect to the direction of gravity 3320 whenthe pressure in the pressurized conduit is below a given set point; thisarm position, in this embodiment, is known as the closed position, andcorresponds to the stop 3308 covering the port 3306. When the pressurein the conduit exceeds the set point, a force acts on the stop 3308,which results in a torque acting around the pivot pin 3314. The torqueacts to rotate the arm 3310 around the pivot pin 3314 in acounter-clockwise direction, causing the arm to move away from itsclosed position and exposing the port 3306, which allows fluids toescape from the orifice 3304. When the pressure in the conduit isrelieved below the set point, the force of gas is no longer sufficientto keep the arm 3310 away from its closed position; thus, the arm 3310returns to the closed position, and the stop 3308 covers the port 3306.

Still referring to FIGS. 33 and 33A, the arm 3310 acts as a lever increating adjustable moments and serves to multiply the force applied bythe counter mass 3316 through the stop 3308 to the port 3306. This forcemultiplication reduces the weight needed to close the orifice 3304 asopposed to a design where the stop 3308 alone acts vertically on top ofthe orifice 3304, as in a pressure cooker. Thus a large port size, topromote expedited venting from a pressurized conduit, may be covered bya relatively lightweight, large-sized stop, the counter mass acting toadjust the desired set point; less design effort may be expended inchoosing specific port sizes and stop properties. The addition of anaxis 3318 for adjusting the position of the counter mass 3316, in thepresent embodiment, allows for changes in the multiplier ratio. As thecounter mass 3316 is moved to a position closer to the pivot pin 3314,the multiplier ratio is reduced, creating a lower closing force. If thecounter mass 3316 is moved farther from the pivot pin 3314, themultiplier ratio is increased, hence increasing the closing force.Therefore, the position of the counter mass 3316 effectively acts toadjust the set point of the backpressure regulator.

Adjustment of the backpressure regulator set point may be useful, whenthe backpressure regulator is utilized in apparatus at higher altitudes.When the atmospheric pressure is lower, the apparatus operating pressureis commensurately lower. As a result, the temperature of thedistillation apparatus is lowered, which may adversely affect apparatusperformance. As well, such adjustment allows one to identify set pointsfor the backpressure regulator that are desired by the end user. The useof a counter mass to apply the closing force may also lower cost of thebackpressure regulator and reduce component fatigue. In a particularembodiment, the adjustable counter mass is designed to allow a range ofset points with a lowest set point substantially less than or equal to10 psig and a highest set point substantially greater than or equal to17 psig. Thus various embodiments allow for precise apparatus pressureregulation, unlike devices which act simply as safety relief valves.

Referring now to FIGS. 33B-C, these figures illustrate an alternateembodiment of the back pressure regulator 3300 having an orifice 3326configured such that the port 3328 is oriented vertically with respectto the direction of gravity 3320. Thus other embodiments may accommodateany orifice orientation while maintaining the use of an adjustablecounter mass.

The backpressure regulator may be configured to allow a small leakagerate below the set point in order to purge the build up of volatilegases that act to insulate heat exchange and suppress boiling in asystem; the regulator is designed, however, to allow-pressure to buildin the pressurized conduit despite this small leakage. In one embodimentrelease of volatile components from a pressurized conduit, below the setpoint of the backpressure regulator, may also be achieved through aspecifically-designed leak vent while the arm of the backpressureregulator is in the closed position. The leak vent is configured toallow a certain leakage rate from the port or the orifice while thepressure in the conduit is below the set point. Such leak vent may bedesigned by a variety of means known to those skilled in the art.Non-limiting examples include specific positioning of the stop and portto allow a small opening while the arm is in the closed position;designing the port such that a small opening, not coverable by the stop,is always exposed; specifying a particular rigid, non-compliant sealconfiguration between the stop and port when the arm is in the closedposition; and configuring the orifice leading to the port to have asmall opening to allow leakage of fluids.

Referring now FIGS. 33D-G, these figures illustrate alternateembodiments of the back pressure regulator 3300 allowing the leakage ofvolatiles below the set point. In one alternate embodiment, the port3332 has a notch 3334 as shown in FIG. 33D and the close-up of region Cof FIG. 33D depicted in FIG. 33E. Thus, when a stop is in contact withthe port 3332, and the arm of the backpressure regulator is in theclosed position, a leak vent is present at the position of the notch3334 that allows a leakage of fluid. In another alternate embodiment ofthe backpressure regulator 3300, orifice 3336 has a small opening 3338,as depicted in FIG. 33F and blow up of region E of FIG. 33F depicted inFIG. 33G. The opening 3338 is configured such that a leak vent iscreated when the stop covers the port 3336 since fluids may leak throughthe opening 3338.

Various features of a backpressure regulator may be altered or modified.For example, stops to be used with backpressure regulators may have anyshape, size, or mass consistent with desired operating conditions, suchstops need not be ball-shaped as shown in some embodiments discussedherein. As well, stops of different weight but similar sizes may beutilized with the retainer to alter the set point of the regulator.Similarly, counter masses of different sizes, shapes and masses may beutilized with various embodiments with preference that they areaccommodated by the axis and arm configurations (compare 3316 in FIGS.33 and 33A with 3330 in FIGS. 33B and 33C); such counter masses may beattached and oriented relative to the arm by any of a variety oftechniques apparent to those skilled in the art. The pivot pin placementneed not be positioned as shown in FIGS. 33-33C, but may be positionedwherever advantageous to provide the mechanical advantage required toachieve a particular pressure set point.

Referring back to FIG. 33, other embodiments of the backpressureregulator 3300 may optionally utilize the drain orifice featuredescribed earlier. Also, embodiments of the backpressure regulator 3300may not utilize the counter mass force adjustment feature, relying onthe specific properties of a stop to provide the set point for thebackpressure regulator.

Other embodiments of the water vapor distillation apparatus may notutilize a vessel, but rely on orifices that are intrinsically part ofthe system. In such instances, the backpressure regulator arm may bedirectly attached to a portion of the system such that the arm, stop,and counter mass are appropriately oriented for the operation of theregulator.

Now referring to FIG. 34, the vessel 3302 includes a drain orifice 3322.Since the backpressure regulator 3300 may operate within a boundedregion 3402 of a large system 3400, the drain orifice 3322 acts as apathway to release fluids that are purged from the pressurized conduit3404 through orifice 3304 into the bounded region 3402. The drainorifice 3322 may connect the bounded region 3402 to another area of thelarger system, or to the external environment 3406. In addition, thebuild-up of gases in the bounded region 3402 may result in condensationof such gases. Also, gases purged through the orifice 3304 may beentrained with droplets of fluid that may accumulate in the boundedregion 3402. Thus the drain orifice 3322 may also be used to purge anybuild up of condensables that accumulate in the bounded region 3402; thecondensables may also be released from the bounded region using aseparate orifice 3408.

Referring now to FIG. 35, in alternate embodiments the apparatus maymaintain a constant blowdown water flow to prevent scaling and otheraccumulation in the apparatus as follows. Water level 3502 in headchamber 3504 is adjusted through a feedback control loop using levelsensor L1, valve V1, and source pump 3506, to maintain proper water flowthrough the blowdown stream 3508. The three-way source pump fill valve3510 is set to pump water into sump 3512, which causes water level 3502in head chamber 3504 to rise. As fluid level 3502 rises in head chamber3504, fluid overflows past a dam-like barrier 3514 into blowdown controlchamber 3516 containing blowdown level sensor L1. As required, blowdownvalve V1 is controlled to allow water flow from blowdown control chamber3516 through heat exchanger 3518, to extract heat and cool blowdownstream 3508, and flow out valve V1, through volatile mixer 3520 allowingcooling of hot gases and steam 3522 from the evaporator section 3524,and then completing the blowdown stream, out to waste 3526.

Still referring to FIG. 35, the apparatus may also maintain properproduct flow as follows. Product level 3528 builds up in condenserchamber 3530, and enters into product control chamber 3532, whereproduct level sensor L2 is housed. Using a feedback control loop withlevel sensor L2 and valve V2, product stream 3534 is controlled to flowfrom product control chamber 3532 through heat exchanger 3518, toextract heat and cool product stream 3534, then through valve V2 and onout to complete the product stream as product water outlet 3536.

The system may preferably be configured to maintain proper liquid ringpump 3538 water level by the use of a fluid recovery system to replenishfluid loss. There are several ways that fluid from the ring pump may bedepleted during system operation, including leakage into lower reservoir3540, expulsion through exhaust port 3542, and evaporation. The leakageand expulsion losses may be large depending on operational parameters,such as the speed of rotation and liquid ring pump 3538 throughput.These leakage and expulsion losses could require total replacement ofthe fluid in the pump several times per hour. The evaporation loss istypically small.

Referring to FIG. 35, the fluid level in the ring pump 3538 may bemaintained by adding additional source water, product water, orpreferably by re-circulating liquid water lost from the liquid ring pumpfor improved system efficiency. In one embodiment the fluid level in thering pump 3538 is primarily maintained by re-circulation of the fluidaccumulated in lower reservoir 3540. Fluid may accumulate in lowerreservoir 3540 from leakage from the liquid ring pump 3538 and fromfluid expelled in exhaust 3542, captured in mist eliminator 3544 andpumped to lower reservoir 3540. Alternatively, fluid expelled in exhaust3542 and captured in mist eliminator 3544 may be returned via the liquidring pump exhaust port. Fluid accumulated in lower reservoir may bere-circulated by one of several pumping mechanisms. One exemplary methodis to use a siphon pump.

Still referring to FIG. 35, a minimum depth of water is preferablymaintained in the lower reservoir for the siphon pump to performproperly. In one embodiment liquid ring pump control chamber 3546, whichhouses liquid ring pump level sensor L3 may be used to control theliquid ring pump level and control the level of water in the lowerreservoir 3540. Liquid ring pump control chamber 3546 is fluidlyconnected to liquid ring pump 3538 and lower reservoir 3540. Liquid ringpump 3538 is connected to the three-way source fill valve 3510, which isset to open when the liquid ring pump 3538 requires more water and it isalso connected to the liquid ring pump drain valve V3, which opens whenit is required to drain water from liquid ring pump 3538 into blowdownstream 3508.

Still referring to FIG. 35, if re-circulated water front lower reservoir3540 is not primarily used to maintain the fluid level in the liquidring pump 3538, then either cold source water or product water could tobe used. In the event source water were used, the introduction of coldwater (which could be approximately 85 degrees C. colder than systemtemperature) to the liquid ring pump 3538 would decrease systemefficiency or alternatively the use of a pre-heater for such cold sourcewater would increase the energy budget of the system. Alternatively, theuse of product water, while not adversely affecting system temperature,could decrease production level and, thus, also lead to systeminefficiency. At startup, the initial fluid level for the liquid ringpump is preferably supplied from source water.

Now referring to FIG. 35A, in one embodiment the start-up time may bereduced by using an external connecting valve 3550 between source 3548and blowdown 3508 fluid lines, located adjacent to heat exchanger 3518,on the cold side. To determine the level of fluid in evaporator head3504 during the initial fill, connecting valve 3550 would be open,blowdown valve BV would be closed, and fluid would be pumped into thesystem through source line 3548. Connecting blowdown 3508 and source3548 lines results in equal fluid height in the blowdown level sensorhousing 3516 and evaporator head 3504, thereby permitting adetermination of fluid level in evaporator head 3504 and enabling theevaporator to be filled to the minimum required level at startup. Usingthe minimum level required shortens initial warm-up time and preventsspill-over from the evaporator head 3504 through the liquid ring pump3538 to the condenser 3552 when the liquid ring pump 3538 startsillustrated on FIG. 35.

Still referring to FIG. 35A, the concentration of solids in blowdownstream 3508 may be monitored and controlled to prevent precipitation ofmaterials from solution and thus clogging of the system. Also duringstart-up, circulating pump 3554 may circulate water through heatexchanger 3518 to pre-heat the heat exchanger to the proper temperaturefor normal operation. A conductivity sensor (not shown) may be used todetermine total dissolved solid (TDS) content by measuring theelectrical conductivity of the fluid. In a particular embodiment, thesensor is an inductive sensor, whereby no electrically conductivematerial is in contact with the fluid stream. If the TDS content inblowdown stream 3508 rises above a prescribed level, for example, duringdistillation of sea water, the fluid source feed rate is increased.Increasing the fluid source feed rate will increase the rate of blowdownstream 3508, because distilled water production changes only slightly asa function of fluid feed rate, and an increased blowdown stream rateresults in reduced concentration of TDS, thereby maintaining overallefficiency and productivity of the system.

Alternate embodiments may also include a fluid control system usinglevel sensors and variable flow valves in a feedback configuration.Optimal operation of the still requires total fluid flow in to closelymatch total fluid flow out. Maintaining fluid levels in the still atnear constant levels accomplishes this requirement. In a particularembodiment, the sensors are capacitive level sensors, a particularlyrobust sensor for measuring fluid levels. Capacitive level sensors haveno moving parts and are insensitive to fouling, and manufacture issimple and inexpensive. Opening of a variable flow valve is controlledby the level of fluid measured by the capacitive level sensor, wherebythe fluid level is adjusted at the level sensor location. A rising fluidlevel causes the valve to open more, increasing flow out of the sensorvolume. Conversely, a falling fluid level causes the valve to closemore, decreasing flow out of the sensor volume.

Flow rate through the variable flow control valves and from the inputpump may be determined using an in-situ calibration technique. The levelsensors and associated level sensor volume may be used to determine thefill or empty rate of the sensor volume. By appropriately configuringthe control valves, the flow rate calibration of each valve and also ofthe source pump may be determined.

In one embodiment, a valve block (not shown) may be utilized toconsolidate all control valves for the system into a single part, whichmay be integrated with the fluid flow manifold. A control systemcomprising a sensor for total dissolved solids and blowdown stream mayalso be incorporated, as well as a float valve or other device forcontrolling the height/level of fluid in the head.

Referring back to FIG. 35, there is additionally a steam flow line 3554from head 3504 to compressor 3538, a steam outlet 3542 for divertingsteam to evaporator/condenser, a hot product line 3534 fromevaporator/condenser leading through exchanger 3518, which also allowsfor collection of hot purified condensed product 3528, and a line (notshown) for diverting hot product to compressor 3538 to allow adjustmentof water level to keep it constant. There may also be a drain line (notshown), for when the system is shut down.

Referring now to FIGS. 36-36C, alternate embodiments may also include afluid distribution manifold 3600. FIG. 36 shows one face of the pumpside of one particular embodiment of a fluid distribution manifold 3600.Input, in the form of raw source feed, flows through port 3602, andblowdown stream (output) flows through port 3604. Additional output inthe form of product flows through port 3606, while port/chamber 3608provides the vent for volatiles (output) and port 3610 provides thedrain (output) for liquid ring pump. FIG. 36A shows the other face ofthe pump side of the same particular embodiment of fluid distributionmanifold 3600. Port/chamber 3608, for output of volatiles, is apparent,as is the drain 3610 for a liquid ring pump. In this view of thisparticular embodiment, a condenser steam mist eliminator chamber 3612 isvisible, as is a mist collector and drain area 3614.

Referring specifically to FIG. 36B, this figure illustrates one face ofthe evaporator/condenser side of the same particular embodiment of fluiddistribution manifold 3600. Raw source feed port 3602, as well asblowdown passage ports 3604 and product passage ports 3606 are readilyvisible in this view. In addition, evaporator steam passage port 3616and condenser steam passage port 3618 may be seen.

Referring specifically to FIG. 36B, this figure illustrates the otherface of the evaporator/condenser side of the same particular embodimentof fluid distribution manifold 3600. Again blowdown passage port 3604 isvisible, as is liquid ring pump drain port 3606, a second condensersteam mist eliminator 3612, evaporator steam mist eliminator 3620, andmist collector and drain area 3614. Also, a sump level control chambercan be seen in this view, along with a product level control chamber3622 and a liquid ring pump supply feed 3624.

Still referring to FIGS. 36-36C, a fluid distribution manifold 3600 iscapable of eliminating most plumbing in a fluid purification system,advantageously incorporating various functionality in one unit,including flow regulation, mist removal, and pressure regulation,thereby simplifying manufacture and significantly reducing overallcomponent parts. The core plates and manifolds may be made of, forexample, plastic, metal, or ceramic plates, or any other non-corrosivematerial capable of withstanding high temperature and pressure. Methodsof manufacture for the core plates and manifolds include brazing andover-molding.

Referring now to FIGS. 37-37A, these figures illustrate a fittingassembly that allows fluid interfacing throughout the system in aparticular embodiment. For example, there may be a floating fluidinterface between the exchanger 3518 (shown on FIG. 35) and theintake/exhaust ports 3220 and 3208 (shown on FIG. 32). FIG. 37Aillustrates a connector 3702 that may be welded to the heat exchangerports (not shown), wherein the connector 3702 connects to the fluidinterface 3704 which is in turn in communication with the fluiddistribution manifold. FIG. 37A shows a sectional view across line A-A(see FIG. 37). The connector 3702 has the ability to float to compensatefor shifts in registration, possibly caused by temperature ormanufacturing variations. Sealing is accomplished by the o-ring 3706. Ascan be seen in the view depicted in FIG. 37, the o-ring seal 3706, uponrotation of line A-A 90 degree about a central axis, the connector 3702and the fluid interface 3704 lock together to make a fluid interfaceconnection.

Referring now to FIGS. 38-38A, these figures illustrate anotherembodiment of the evaporator/condenser 3800. As seen in FIG. 38,evaporator/condenser 3800 is a flat evaporator/condenser and containsmultiple parallel core layers 3802 and 3804, typically made ofcopper-nickel alloy or other heat-transferable material, with ribsections 3806 creating channels 3810 and 3812 for directing steam andcondensed fluid flow. Steam intake 3814 and product exit 3816 manifolds(as well as dirty intake and volatile exit manifolds, not shown) mayconnect via a fluid interface to a liquid ring pump/compressor. Bolts3818 secure core evaporator/condenser 3800 to brackets of externalhousing of the liquid ring pump/compressor. In operation, everyalternating horizontal (as shown in FIGS. 38 and 38A) row 3802 and 3804comprises evaporator channels 3810 and condenser channels 3812, suchthat the two functions never overlap on any given layer. FIG. 38A, adetail of FIG. 38, shows more clearly how the combinedevaporator/condenser manifolds works. As indicated, rows 3802 do notinteract with rows 3804, they are closed off to each other, therebyseparating the functions of evaporation and condensation in thehorizontal core layers.

Referring now to FIG. 39, this figure illustrates alternate embodimentof the heat exchanger used in the water vapor distillation apparatus,wherein such heat exchangers capitalize on available systemic and heatsources. In one particular embodiment, heat from at least one of aplurality of sources passes through a multi-line heat exchanger 3902such as depicted in FIG. 39, wherein a series of two-channel heatexchangers such as 3904, 3906, 3908, and 3910 are plumbed to produce amulti-line effect. Note that in the particular multi-line heat exchangerembodiment shown in FIG. 39, the flow of cold intake 3912 passes throughall heat exchanger units 3904, 3906, 3908, and 3910; one heat source,for example hot product 3914, flows through heat exchanger units 3904and 3908; and another heat source, for example hot blowdown stream 3916,flows through heat exchange units 3906 and 3910. In this way, multipleheat sources may be used to exchange with the cold intake flow 3912.

Now referring to FIG. 39A, this figure illustrates an alternateembodiment of the heat exchanger. In this embodiment, the heat exchangermay be a single multi-channel heat exchanger 3918. In this particularembodiment, cold intake 3912, and heat sources such as hot product 3914and hot blowdown stream 3916, for example, flow through exchanger 3918simultaneously, but in opposite directions, thereby enabling heatexchange with cold intake 3912 from both heat sources 3914 and 3916within a single heat exchanger 3912.

Referring now to FIG. 40, one alternate embodiment may include measuringthe evaporator and condenser pressures to assess overall systemperformance and/or provide data to a control system. To avoid the use ofexpensive sensors that would be required to withstand the elevatedtemperatures of evaporator/condenser 4002, pressure sensors P_(E) andP_(C) are mounted on fluid lines between the cold side of heat exchanger4004 and corresponding control valves V_(E) and V_(C). To avoidmeasuring a pressure less than the actual pressure of the system, whichwould occur when fluid is flowing for pressure sensors located at thisposition, the control valve would be closed momentarily to stop flow.During the “no-flow” period, pressure will be constant from the controlvalve back to the evaporator or condenser, enabling accurate measurementof the system pressure. No adverse effects on still performance willoccur from these short “no-flow” periods.

Referring now to FIGS. 41-41B, this figure illustrates anotherembodiment of the present disclosure including a filtering mechanismwithin intake to increase the purity of the final product fluid. A multiunit flip-filter 4100, having a pivot joint 4102 joining at least twofilter units 4104 and 4106, is situated within a filter housing 4108which directs fluid through filter units 4104 and 4106 and facilitatesrotation of filter units 4104 and 4106 about central pivot joint 4102.As shown, blowdown stream 4109 passes through flip-filter unit 4104,while intake fluid stream 4110 simultaneously flows from intake throughflip-filter unit 4106 en route to purification. After some interval aflip-filter switch (not shown), rotates flip-filter 4100 around itscentral axis, shown by the dotted line, at flip-filter pivot joint 4102,such that filter unit 4106, now fouled with contaminates filtered fromdirty intake fluid, is backwashed by blowdown stream 4109, and filterunit 4104 becomes the filter unit which filters intake fluid stream4110. In such an embodiment, o-ring gaskets 4112 and 4114 may beutilized as seals between filter units 4104 and 4106 and the fluid flowroutes of blow-down stream 4109 and intake fluid stream 4110,respectively.

Referring now to FIGS. 41C-D, the multi-unit flip filter may be amulti-sected circular filter 4112. Multi unit flip-filter 4112, having apivot point 4114 about which multiple flip-filter units such as 4116 and4118 pivot, may also be situated within filter housing 4120 that directsfluid flow through individual filter units 4116 and 4118 and facilitatesrotation of filter 4112 about pivot point 4114. As shown, blowdownstream 4109 passing through one flip-filter unit 4116, while intakefluid stream 4110 simultaneously flows from intake through flip-filterunit 4118 en route to purification. As in FIG. 41, a flip-filter switch(not shown), rotates flip-filter 4112 around its central axis, shown bythe dotted line, at flip-filter pivot point 4114, such that filter unit4118, now fouled with contaminates filtered from dirty intake fluid, isbackwashed by blowdown stream 4109, and filter unit 4116 becomes thefilter unit which filters intake fluid stream 4110. A series of seals,as indicated by 4122 and 4124, are utilized between individual filterunits 4116 and 4118, to partition blowdown stream 4109 flowing throughone filter section, from intake fluid stream 4110 flowing throughanother filter section.

Now referring to FIGS. 41E-41F, other embodiments may include a manualvalve 4122 to change the direction of water flow. Such a valve allowsuse of, for example, blowdown stream 4109 to continuously clean one unitof each flip-filter, and with a single operation effectively switcheswhich unit is being filtered and which unit is being back-washed,thereby back-washing filter units 4104 or 4106 without the need toactually flip filter 4100 itself. In one particular embodiment whenvalve 4122 is in position A, filter unit 4104 is filtering intake fluid4110, and filter unit 4106 is being back-washed with blowdown stream4109. Upon switching valve 4100 to position B, filter unit 4104 is nowbeing backwashed by blowdown stream 4108, and filter unit 4106 is nowfiltering input fluid 4110.

Stirling Cycle Engine

The various embodiments of the water vapor distillation apparatusdescribed above may, in some embodiment, may be powered by a Stirlingcycle machine (also may be referred to as a Stirling engine). In theexemplary embodiment, the Stirling cycle machine is a Stirling enginedescribed in pending U.S. patent application Ser. No. 12/105,854 havingAttorney Docket No. 170 filed on Apr. 18, 2008, which is hereinincorporated by reference in its entirety. However, in otherembodiments, the Stirling cycle machine may be any of the Stirling cyclemachines described in the following references, all of which areincorporated by reference in their entirely: U.S. Pat. Nos. 6,381,958;6,247,310; 6,536,207; 6,705,081; 7,111,460; and 6,694,731.

Stirling cycle machines, including engines and refrigerators, have along technological heritage, described in detail in Walker, StirlingEngines, Oxford University Press (1980), incorporated herein byreference. The principle underlying the Stirling cycle engine is themechanical realization of the Stirling thermodynamic cycle:isovolumetric heating of a gas within a cylinder, isothermal expansionof the gas (during which work is performed by driving a piston),isovolumetric cooling, and isothermal compression. Additional backgroundregarding aspects of Stirling cycle machines and improvements thereto isdiscussed in Hargreaves, The Phillips Stirling Engine (Elsevier,Amsterdam, 1991), which is herein incorporated by reference.

The principle of operation of a Stirling cycle machine is readilydescribed with reference to FIGS. 51A-51E, wherein identical numeralsare used to identify the same or similar parts. Many mechanical layoutsof Stirling cycle machines are known in the art, and the particularStirling cycle machine designated generally by numeral 5110 is shownmerely for illustrative purposes. In FIGS. 51A to 51D, piston 5112 and adisplacer 5114 move in phased reciprocating motion within the cylinders5116 which, in some embodiments of the Stirling cycle machine, may be asingle cylinder, but in other embodiments, may include greater than asingle cylinder. A working fluid contained within cylinders 5116 isconstrained by seals from escaping around piston 5112 and displacer5114. The working fluid is chosen for its thermodynamic properties, asdiscussed in the description below, and is typically helium at apressure of several atmospheres, however, any gas, including any inertgas, may be used, including, but not limited to, hydrogen, argon, neon,nitrogen, air and any mixtures thereof. The position of the displacer5114 governs whether the working fluid is in contact with the hotinterface 5118 or the cold interface 5120, corresponding, respectively,to the interfaces at which heat is supplied to and extracted from theworking fluid. The supply and extraction of heat is discussed in furtherdetail below. The volume of working fluid governed by the position ofthe piston 5112 is referred to as the compression space 5122.

During the first phase of the Stirling cycle, the starting condition ofwhich is depicted in FIG. 51A, the piston 5112 compresses the fluid inthe compression space 5122. The compression occurs at a substantiallyconstant temperature because heat is extracted from the fluid to theambient environment. The condition of the Stirling cycle machine 5110after compression is depicted in FIG. 51B. During the second phase ofthe cycle, the displacer 5114 moves in the direction of the coldinterface 5120, with the working fluid displaced from the region of thecold interface 5120 to the region of the hot interface 5118. This phasemay be referred to as the transfer phase. At the end of the transferphase, the fluid is at a higher pressure since the working fluid hasbeen heated at constant volume. The increased pressure is depictedsymbolically in FIG. 51C by the reading of the pressure gauge 5124.

During the third phase (the expansion stroke) of the Stirling cyclemachine, the volume of the compression space 5122 increases as heat isdrawn in from outside the Stirling cycle machine 5110, therebyconverting heat to work. In practice, heat is provided to the fluid bymeans of a heater head (not shown) which is discussed in greater detailin the description below. At the end of the expansion phase, thecompression space 5122 is full of cold fluid, as depicted in FIG. 51D.During the fourth phase of the Stirling cycle machine 5110, fluid istransferred from the region of the hot interface 5118 to the region ofthe cold interface 5120 by motion of the displacer 5114 in the opposingsense. At the end of this second transfer phase, the fluid fills thecompression space 5122 and cold interface 5120, as depicted in FIG. 51A,and is ready for a repetition of the compression phase. The Stirlingcycle is depicted in a P-V (pressure-volume) diagram as shown in FIG.51E.

Additionally, on passing from the region of the hot interface 5118 tothe region of the cold interface 5120. In some embodiments, the fluidmay pass through a regenerator (shown as 5408 in FIG. 54). A regeneratoris a matrix of material having a large ratio of surface area to volumewhich serves to absorb heat from the fluid when it enters from theregion of the hot interface 5118 and to heat the fluid when it passesfrom the region of the cold interface 5120.

Stirling cycle machines have not generally been used in practicalapplications due to several daunting challenges to their development.These involve practical considerations such as efficiency and lifetime.Accordingly, there is a need for more Stirling cycle machines withminimal side loads on pistons, increased efficiency and lifetime.

The principle of operation of a Stirling cycle machine or Stirlingengine is further discussed in detail in U.S. Pat. No. 6,381,958, issuedMay 7, 2002, to Kamen et al., which is herein incorporated by referencein its entirety.

Rocking Beam Drive

Referring now to FIGS. 52-54, embodiments of a Stirling cycle machine,according to one embodiment, are shown in cross-section. The engineembodiment is designated generally by numeral 5300. While the Stirlingcycle machine will be described generally with reference to the Stirlingengine 5300 embodiments shown in FIGS. 52-54, it is to be understoodthat many types of machines and engines, including but not limited torefrigerators and compressors may similarly benefit from variousembodiments and improvements which are described herein, including butnot limited to, external combustion engines and internal combustionengines.

FIG. 52 depicts a cross-section of an embodiment of a rocking beam drivemechanism 5200 (the term “rocking beam drive” is used synonymously withthe term “rocking beam drive mechanism”) for an engine, such as aStirling engine, having linearly reciprocating pistons 5202 and 5204housed within cylinders 5206 and 5208, respectively. The cylindersinclude linear bearings 5220. Rocking beam drive 5200 converts linearmotions of pistons 5202 and 5204 into the rotary motion of a crankshaft5214. Rocking beam drive 5200 has a rocking beam 5216, rocker pivot5218, a first coupling assembly 5210, and a second coupling assembly5212. Pistons 5202 and 5204 are coupled to rocking beam drive 5200,respectively, via first coupling assembly 5210 and second couplingassembly 5212. The rocking beam drive is coupled to crankshaft 5214 viaa connecting rod 5222.

In some embodiments, the rocking beam and a first portion of thecoupling assembly may be located in a crankcase, while the cylinders,pistons and a second portion of the coupling assembly is located in aworkspace.

In FIG. 54 a crankcase 5400 most of the rocking beam drive 5200 ispositioned below the cylinder housing 5402. Crankcase 5400 is a space topermit operation of rocking beam drive 5200 having a crankshaft 5214,rocking beam 5216, linear bearings 5220, a connecting rod 5222, andcoupling assemblies 5210 and 5212. Crankcase 5400 intersects cylinders5206 and 5208 transverse to the plane of the axes of pistons 5202 and5204. Pistons 5202 and 5204 reciprocate in respective cylinders 5206 and5208, as also shown in FIG. 52. Cylinders 5206 and 5208 extend abovecrankshaft housing 5400. Crankshaft 5214 is mounted in crankcase 5400below cylinders 5206 and 5208.

FIG. 52 shows one embodiment of rocking beam drive 5200. Couplingassemblies 5210 and 5212 extend from pistons 5202 and 5204,respectively, to connect pistons 5202 and 5204 to rocking beam 5216.Coupling assembly 5212 for piston 5204, in some embodiments, maycomprise a piston rod 5224 and a link rod 5226. Coupling assembly 5210for piston 5202, in some embodiments, may comprise a piston rod 5228 anda link rod 5230. Piston 5204 operates in the cylinder 5208 verticallyand is connected by the coupling assembly 5212 to the end pivot 5232 ofthe rocking beam 5216. The cylinder 5208 provides guidance for thelongitudinal motion of piston 5204. The piston rod 5224 of the couplingassembly 5212 attached to the lower portion of piston 5204 is drivenaxially by its link rod 5226 in a substantially linear reciprocatingpath along the axis of the cylinder 5208. The distal end of piston rod5224 and the proximate end of link rod 5226, in some embodiments, may bejointly hinged via a coupling means 5234. The coupling means 5234, maybe any coupling means known in the art, including but not limited to, aflexible joint, roller bearing element, hinge, journal bearing joint(shown as 5600 in FIG. 56), and flexure (shown as 5700 in FIGS. 57A and57B). The distal end of the link rod 5226 may be coupled to one endpivot 5232 of rocking beam 5216, which is positioned vertically andperpendicularly under the proximate end of the link rod 5226. Astationary linear bearing 5220 may be positioned along coupling assembly5212 to further ensure substantially linear longitudinal motion of thepiston rod 5224 and thus ensuring substantially linear longitudinalmotion of the piston 5204. In an exemplary embodiment, link rod 5226does not pass through linear bearing 5220. This ensures, among otherthings, that piston rod 5224 retains a substantially linear andlongitudinal motion.

In the exemplary embodiment, the link rods may be made from aluminum,and the piston rods and connecting rod are made from D2 Tool Steel.Alternatively, the link rods, piston rods, connecting rods, and rockingbeam may be made from 4340 steel. Other materials may be used for thecomponents of the rocking beam drive, including, but not limited to,titanium, aluminum, steel or cast iron. In some embodiments, the fatiguestrength of the material being used is above the actual load experiencedby the components during operation.

Still referring to FIGS. 52-54, piston 5202 operates vertically in thecylinder 5206 and is connected by the coupling assembly 5210 to the endpivot 5236 of the rocking beam 5216. The cylinder 5206 serves, amongstother functions, to provide guidance for longitudinal motion of piston5202. The piston rod 5228 of the coupling assembly 5210 is attached tothe lower portion of piston 5202 and is driven axially by its link rod5230 in a substantially linear reciprocating path along the axis of thecylinder 5206. The distal end of the piston rod 5228 and the proximateend of the link rod 5230, in some embodiments, is jointly hinged via acoupling means 5238. The coupling means 5238, in various embodiments mayinclude, but are not limited to, a flexure (shown as 5700 in FIGS. 57Aand 57B, roller bearing element, hinge, journal bearing (shown as 5600in FIG. 56), or coupling means as known in the art. The distal end ofthe link rod 5230, in some embodiments, may be coupled to one end pivot5236 of rocking beam 5216, which is positioned vertically andperpendicularly under the proximate end of link rod 5230. A stationarylinear bearing 5220 may be positioned along coupling assembly 5210 tofurther ensure linear longitudinal motion of the piston rod 5228 andthus ensuring linear longitudinal motion of the piston 5202. In anexemplary embodiment, link rod 5230 does not pass through linear bearing5220 to ensure that piston rod 5228 retains a substantially linear andlongitudinal motion.

The coupling assemblies 5210 and 5212 change the alternatinglongitudinal motion of respective pistons 5202 and 5204 to oscillatorymotion of the rocking beam 5216. The delivered oscillatory motion ischanged to the rotational motion of the crankshaft 5214 by theconnecting rod 5222, wherein one end of the connecting rod 5222 isrotatably coupled to a connecting pivot 5240 positioned between an endpivot 5232 and a rocker pivot 5218 in the rocking beam 5216, and anotherend of the connecting rod 5222 is rotatably coupled to crankpin 5246.The rocker pivot 5218 may be positioned substantially at the midpointbetween the end pivots 5232 and 5236 and oscillatorily support therocking beam 5216 as a fulcrum, thus guiding the respective piston rods5224 and 5228 to make sufficient linear motion. In the exemplaryembodiment, the crankshaft 5214 is located above the rocking beam 5216,but in other embodiments, the crankshaft 5214 may be positioned belowthe rocking beam 5216 (as shown in FIGS. 55B and 55D) or in someembodiments, the crankshaft 5214 is positioned to the side of therocking beam 5216, such that it still has a parallel axis to the rockingbeam 5216.

Still referring to FIGS. 52-54, the rocking beam oscillates about therocker pivot 5218, the end pivots 5232 and 5236 follow an arc path.Since the distal ends of the link rods 5226 and 5230 are connected tothe rocking beam 5216 at pivots 5232 and 5236, the distal ends of thelink rods 5226 and 5230 also follow this arc path, resulting in anangular deviation 5242 and 5244 from the longitudinal axis of motion oftheir respective pistons 5202 and 5204. The coupling means 5234 and 5238are configured such that any angular deviation 5244 and 5242 from thelink rods 5226 and 5230 experienced by the piston rods 5224 and 5228 isminimized. Essentially, the angular deviation 5244 and 5242 is absorbedby the coupling means 5234 and 5238 so that the piston rods 5224 and5228 maintain substantially linear longitudinal motion to reduce sideloads on the pistons 5204 and 5202. A stationary linear bearing 5220 mayalso be placed inside the cylinder 5208 or 5206, or along couplingassemblies 5212 or 5210, to further absorb any angular deviation 5244 or5242 thus keeping the piston push rod 5224 or 5228 and the piston 5204or 5202 in linear motion along the longitudinal axis of the piston 5204or 5202.

Therefore, in view of reciprocating motion of pistons 5202 and 5204, itis necessary to keep the motion of pistons 5202 and 5204 as close tolinear as possible because the deviation 5242 and 5244 from longitudinalaxis of reciprocating motion of pistons 5202 and 5204 causes noise,reduction of efficiency, increase of friction to the wall of cylinder,increase of side-load, and low durability of the parts. The alignment ofthe cylinders 5206 and 5208 and the arrangement of crankshaft 5214,piston rods 5224 and 5228, link rods 5226 and 5230, and connecting rod5222, hence, may influence on, amongst other things, the efficiencyand/or the volume of the device. For the purpose of increasing thelinearity of the piston motion as mentioned, the pistons (shown as 5202and 5204 in FIGS. 52-54) are preferably as close to the side of therespective cylinders 5206 and 5208 as possible.

In another embodiment reducing angular deviation of link rods, link rods5226 and 5230 substantially linearly reciprocate along longitudinal axisof motion of respective pistons 5204 and 5202 to decrease the angulardeviation and thus to decrease the side load applied to each piston 5204and 5202. The angular deviation defines the deviation of the link rod5226 or 5230 from the longitudinal axis of the piston 5204 or 5202.Numerals 5244 and 5242 designate the angular deviation of the link rods5226 and 5230, as shown in FIG. 52. Therefore, the position of couplingassembly 5212 influences the angular displacement of the link rod 5226,based on the length of the distance between the end pivot 5232 and therocker pivot 5218 of the rocking beam 5216. Thus, the position of thecoupling assemblies may be such that the angular displacement of thelink rod 5226 is reduced. For the link rod 5230, the length of thecoupling assembly 5210 also may be determined and placed to reduce theangular displacement of the link rod 5230, based on the length of thedistance between the end pivot 5236 and the rocker pivot 5218 of therocking beam 5216. Therefore, the length of the link rods 5226 and 5230,the length of coupling assemblies 5212 and 5210, and the length of therocking beam 5216 are significant parameters that greatly influenceand/or determine the angular deviation of the link rods 5226 and 5230 asshown in FIG. 52.

The exemplary embodiment has a straight rocking beam 5216 having the endpoints 5232 and 5236, the rocker pivot 5218, and the connecting pivot5240 along the same axis. However, in other embodiments, the rockingbeam 5216 may be bent, such that pistons may be placed at angles to eachother, as shown in FIGS. 55C and 55D.

Referring now to FIGS. 52-54 and FIGS. 57A-57B, in some embodiments ofthe coupling assembly, the coupling assemblies 5212 and 5210, mayinclude a flexible link rod that is axially stiff but flexible in therocking beam 5216 plane of motion between link rods 5226 and 5230, andpistons 5204 and 5202, respectively. In this embodiment, at least oneportion, the flexure (shown as 5700 in FIGS. 57A and 57B), of link rods5226 and 5230 is elastic. The flexure 5700 acts as a coupling meansbetween the piston rod and the link rod. The flexure 5700 may absorb thecrank-induced side loads of the pistons more effectively, thus allowingits respective piston to maintain linear longitudinal movement insidethe piston's cylinder. This flexure 5700 allows small rotations in theplane of the rocking beam 5216 between the link rods 5226 and 5230 andpistons 5204 or 5202, respectively. Although depicted in this embodimentas flat, which increases the elasticity of the link rods 5226 and 5230,the flexure 5700, in some embodiments, is not flat. The flexure 5700also may be constructed near to the lower portion of the pistons or nearto the distal end of the link rods 5226 and 5230. The flexure 5700, inone embodiment, may be made of #D2 Tool Steel Hardened to 58-62 RC. Insome embodiments, there may be more than one flexure (not shown) on thelink rod 5226 or 5230 to increase the elasticity of the link rods.

In alternate embodiment, the axes of the pistons in each cylinderhousing may extend in different directions, as depicted in FIGS. 55C and55D. In the exemplary embodiment, the axes of the pistons in eachcylinder housing are substantially parallel and preferably substantiallyvertical, as depicted in FIGS. 52-54, and FIGS. 55A and 55B. FIGS.55A-55D include various embodiments of the rocking beam drive mechanismincluding like numbers as those shown and described with respect toFIGS. 2-4. It will be understood by those skilled in that art thatchanging the relative position of the connecting pivot 5240 along therocking beam 5216 will change the stroke of the pistons.

Accordingly, a change in the parameters of the relative position of theconnecting pivot 5240 in the rocking beam 5216 and the length of thepiston rods 5224 and 5228, link rods 5230 and 5226, rocking beam 5216,and the position of rocker pivot 5218 will change the angular deviationof the link rods 5226 and 5230, the phasing of the pistons 5204 and5202, and the size of the device 5300 in a variety of manner. Therefore,in various embodiments, a wide range of piston phase angles and variablesizes of the engine may be chosen based on the modification of one ormore of these parameters. In practice, the link rods 5224 and 5228 ofthe exemplary embodiment have substantially lateral movement within from−0.5 degree to +0.5 degree from the longitudinal axis of the pistons5204 and 5202. In various other embodiments, depending on the length ofthe link rod, the angle may vary anywhere from approaching 0 degrees to0.75 degrees. However, in other embodiments, the angle may be higherincluding anywhere from approaching 0 to the approximately 20 degrees.As the link rod length increases, however, the crankcase/overall engineheight increases as well as the weight of the engine.

One feature of the exemplary embodiment is that each piston has its linkrod extending substantially to the attached piston rod so that it isformed as a coupling assembly. In one embodiment, the coupling assembly5212 for the piston 5204 includes a piston rod 5224, a link rod 5226,and a coupling means 5234 as shown in FIG. 52. More specifically, oneproximal end of piston rod 5224 is attached to the lower portion ofpiston 5204 and the distal end piston rod 5224 is connected to theproximate end of the link rod 5226 by the coupling means 5234. Thedistal end of the link rod 5226 extends vertically to the end pivot 5232of the rocking beam 5216. As described above, the coupling means 5234may be, but is not limited to, a joint, hinge, coupling, or flexure orother means known in the art. In this embodiment, the ratio of thepiston rod 5224 and the link rod 5226 may determine the angulardeviation of the link rod 5226 as mentioned above.

In one embodiment of the machine, an engine, such as a Stirling engine,employs more than one rocking beam drive on a crankshaft. Referring nowto FIG. 58, an unwrapped “four cylinder” rocking beam drive mechanism5800 is shown. In this embodiment, the rocking beam drive mechanism hasfour pistons 5802, 5804, 5806, and 5808 coupled to two rocking beamdrives 5810 and 5812. In the exemplary embodiment, rocking beam drivemechanism 5800 is used in a Stirling engine comprising at least fourpistons 5802, 5804, 5806, and 5808, positioned in a quadrilateralarrangement coupled to a pair of rocking beam drives 5810 and 5812,wherein each rocking beam drive is connected to crankshaft 5814.However, in other embodiments, the Stirling cycle engine includesanywhere from 14 pistons, and in still other embodiments, the Stirlingcycle engine includes more than 4 pistons. In some embodiments, rockingbeam drives 5810 and 5812 are substantially similar to the rocking beamdrives described above with respect to FIGS. 52-54 (shown as 5210 and5212 in FIGS. 52-54). Although in this embodiment, the pistons are shownoutside the cylinders, in practice, the pistons would be insidecylinders.

Still referring to FIG. 58, in some embodiments, the rocking beam drivemechanism 5800 has a single crankshaft 5814 having a pair oflongitudinally spaced, radially and oppositely directed crank pins 5816and 5818 adapted for being journalled in a housing, and a pair ofrocking beam drives 5810 and 5812. Each rocking beam 5820 and 5822 ispivotally connected to rocker pivots 5824 and 5826, respectively, and tocrankpins 5816 and 5818, respectively. In the exemplary embodiment,rocking beams 5820 and 5822 are coupled to a rocking beam shaft 5828.

In some embodiments, a motor/generator may be connected to thecrankshaft in a working relationship. The motor may be located, in oneembodiment, between the rocking beam drives. In another embodiment, themotor may be positioned outboard. The term “motor/generator” is used tomean either a motor or a generator.

FIG. 59 shows one embodiment of crankshaft 5814. Positioned on thecrankshaft is a motor/generator 5900, such as a Permanent Magnetic(“PM”) generator. Motor/generator 5900 may be positioned between, orinboard of the rocking beam drives (not shown, shown in FIG. 58 as 5810and 5812), or may be positioned outside, or outboard of, rocking beamdrives 5810 and 5812 at an end of crankshaft 5814, as depicted bynumeral 51000 in FIG. 510A.

When motor/generator 5900 is positioned between the rocking beam drives(not shown, shown in FIG. 58 as 5810 and 5812), the length ofmotor/generator 5900 is limited to the distance between the rocking beamdrives. The diameter squared of motor/generator 5900 is limited by thedistance between the crankshaft 5814 and the rocking beam shaft 5828.Because the capacity of motor/generator 5900 is proportional to itsdiameter squared and length, these dimension limitations result in alimited-capacity “pancake” motor/generator 5900 having relatively shortlength, and a relatively large diameter squared. The use of a “pancake”motor/generator 5900 may reduce the overall dimension of the engine,however, the dimension limitations imposed by the inboard configurationresult in a motor/generator having limited capacity.

Placing motor/generator 5900 between the rocking beam drives exposesmotor/generator 5900 to heat generated by the mechanical friction of therocking beam drives. The inboard location of motor/generator 5900 makesit more difficult to cool motor/generator 5900, thereby increasing theeffects of heat produced by motor/generator 5900 as well as heatabsorbed by motor/generator 5900 from the rocking beam drives. This maylead to overheating, and ultimately failure of motor/generator 5900.

Referring to both FIGS. 58 and 59, the inboard positioning ofmotor/generator 5900 may also lead to an unequilateral configuration ofpistons 5802, 5804, 5806, and 5808, since pistons 5802, 5804, 5806, and5808 are coupled to rocking beam drives 5810 and 5812, respectively, andany increase in distance would also result in an increase in distancebetween pistons 5802, 5804, and pistons 5806 and 5808. An unequilateralarrangement of pistons may lead to inefficiencies in burner and heaterhead thermodynamic operation, which, in turn, may lead to a decrease inoverall engine efficiency. Additionally, an unequilateral arrangement ofpistons may lead to larger heater head and combustion chamberdimensions.

The exemplary embodiment of the motor/generator arrangement is shown inFIG. 510A. As shown in FIG. 510A, the motor/generator 51000 ispositioned outboard from rocking beam drives 51010 and 51012 (shown as5810 and 5812 in FIG. 58) and at an end of crankshaft 51006. Theoutboard position allows for a motor/generator 51000 with a largerlength and diameter squared than the “pancake” motor/generator describedabove (shown as 5900 in FIG. 59). As previously stated, the capacity ofmotor/generator 51000 is proportional to its length and diametersquared, and since outboard motor/generator 51000 may have a largerlength and diameter squared, the outboard motor/generator 51000configuration shown in FIG. 510A may allow for the use of a highercapacity motor/generator in conjunction with engine.

By placing motor/generator 51000 outboard of drives 51010 and 51012 asshown in the embodiment in FIG. 510A, motor/generator 51000 is notexposed to heat generated by the mechanical friction of drives 51010 and51012. Also, the outboard position of motor/generator 1000 makes iteasier to cool the motor/generator, thereby allowing for more mechanicalengine cycles per a given amount of time, which in turn allows forhigher overall engine performance.

Also, as motor/generator 51000 is positioned outside and not positionedbetween drives 51010 and 51012, rocking beam drives 51010 and 51012 maybe placed closer together thereby allowing the pistons which are coupledto drives 51010 and 51012 to be placed in an equilateral arrangement. Insome embodiments, depending on the burner type used, particularly in thecase of a single burner embodiment, equilateral arrangement of pistonsallows for higher efficiencies in burner and heater head thermodynamicoperation, which in turn allows higher overall engine performance.Equilateral arrangement of pistons also advantageously allows forsmaller heater head and combustion chamber dimensions.

Referring again to FIGS. 58 and 59, crankshaft 5814 may have concentricends 5902 and 5904, which in one embodiment are crank journals, and invarious other embodiments, may be, but are not limited to, bearings.Each concentric end 5902, 5904 has a crankpin 5816, 5818 respectively,that may be offset from a crankshaft center axis. At least onecounterweight 5906 may be placed at either end of crankshaft 5814 (shownas 51006 in FIG. 510A), to counterbalance any instability the crankshaft5814 may experience. This crankshaft configuration in combination withthe rocking beam drive described above allows the pistons (shown as5802, 5804, 5806, and 5808 in FIG. 58) to do work with one rotation ofthe crankshaft 5814. This characteristic will be further explainedbelow. In other embodiments, a flywheel (not shown) may be placed oncrankshaft 5814 (shown as 51006 in FIG. 510A) to decrease fluctuationsof angular velocity for a more constant speed.

Still referring to FIGS. 58 and 59, in some embodiments, a cooler (notshown) may be also be positioned along the crankshaft 5814 (shown as51006 in FIG. 510A) and rocking beam drives 5810 and 5812 (shown as51010 and 51012 in FIG. 510A) to cool the crankshaft 5814 and rockingbeam drives 5810 and 5812. In some embodiments, the cooler may be usedto cool the working gas in a cold chamber of a cylinder and may also beconfigured to cool the rocking beam drive. Various embodiments of thecooler are discussed in detail below.

FIGS. 510A-510G depict some embodiments of various parts of the machine.As shown in this embodiment, crankshaft 51006 is coupled tomotor/generator 51000 via a motor/generator coupling assembly. Sincemotor/generator 51000 is mounted to crankcase 51008, pressurization ofcrankcase with a charge fluid may result in crankcase deformation, whichin turn may lead to misalignments between motor/generator 51000 andcrankshaft 51006 and cause crankshaft 51006 to deflect. Because rockingbeam drives 51010 and 51012 are coupled to crankshaft 51006, deflectionof crankshaft 51006 may lead to failure of rocking beam drives 51010 and51012. Thus, in one embodiment of the machine, a motor/generatorcoupling assembly is used to couple the motor/generator 51000 tocrankshaft 51006. The motor/generator coupling assembly accommodatesdifferences in alignment between motor/generator 51000 and crankshaft51006 which may contribute to failure of rocking beam drives 51010 and51012 during operation.

Still referring to FIGS. 510A-510G, in one embodiment, themotor/generator coupling assembly is a spline assembly that includesspline shaft 51004, sleeve rotor 51002 of motor/generator 51000, andcrankshaft 51006. Spline shaft 51004 couples one end of crankshaft 51006to sleeve rotor 51002. Sleeve rotor 51002 is attached to motor/generator51000 by mechanical means, such as press fitting, welding, threading, orthe like. In one embodiment, spline shaft 51004 includes a plurality ofsplines on both ends of the shaft. In other embodiments, spline shaft51004 includes a middle splineless portion 51014, which has a diametersmaller than the outer diameter or inner diameter of splined portions51016 and 51018. In still other embodiments, one end portion of thespline shaft 51016 has splines that extend for a longer distance alongthe shaft than a second end portion 51018 that also includes splinesthereon.

In some embodiments, sleeve rotor 51002 includes an opening 51020 thatextends along a longitudinal axis of sleeve rotor 51002. The opening51020 is capable of receiving spline shaft 51004. In some embodiments,opening 51020 includes a plurality of inner splines 51022 capable ofengaging the splines on one end of spline shaft 51004. The outerdiameter 51028 of inner splines 51022 may be larger than the outerdiameter 51030 of the splines on spline shaft 51004, such that the fitbetween inner splines 51022 and the splines on spline shaft 51004 isloose (as shown in FIG. 510E). A loose fit between inner splines 51022and the splines on spline shaft 51004 contributes to maintain splineengagement between spline shaft 51004 and rotor sleeve 51002 duringdeflection of spline shaft 51004, which may be caused by crankcasepressurization. In other embodiments, longer splined portion 51016 ofspline shaft 51004 may engage inner splines 51022 of rotor 51002.

Still referring to FIGS. 510A-510G, in some embodiments, crankshaft51006 has an opening 51024 on an end thereof, which is capable ofreceiving one end of spline shaft 51004. Opening 51024 preferablyincludes a plurality of inner splines 51026 that engage the splines onspline shaft 51004. The outer diameter 51032 of inner splines 51026 maybe larger than the outer diameter 51034 of the splines on spline shaft51004, such that the fit between inner splines 51026 and the splines onspline shaft 51004 is loose (as shown in FIG. 510F). As previouslydiscussed, a loose fit between inner splines 51026 and the splines onspline shaft 51004 contributes to maintain spline engagement betweenspline shaft 51004 and crankshaft 51006 during deflection of splineshaft 51004, which may be caused by crankcase pressurization. The loosefit between the inner splines 51026 and 51022 on the crankshaft 51006and the sleeve rotor 51002 and the splines on the spline shaft 51004 maycontribute to maintain deflection of spline shaft 51004. This may allowmisalignments between crankshaft 51006 and sleeve rotor 51002. In someembodiments, shorter splined portion 51018 of spline shaft 51004 mayengage opening 51024 of crankshaft 51006 thus preventing these potentialmisalignments.

In some embodiments, opening 51020 of sleeve rotor 51002 includes aplurality of inner splines that extend the length of opening 51020. Thisarrangement contributes to spline shaft 51004 being properly insertedinto opening 51020 during assembly. This contributes to proper alignmentbetween the splines on spline shaft 51004 and the inner splines onsleeve rotor 51002 being maintained.

Referring now to FIG. 54, one embodiment of the engine is shown. Herethe pistons 5202 and 5204 of engine 5300 operate between a hot chamber5404 and a cold chamber 5406 of cylinders 5206 and 5208 respectively.Between the two chambers there may be a regenerator 5408. Theregenerator 5408 may have variable density, variable area, and, in someembodiments, is made of wire. The varying density and area of theregenerator may be adjusted such that the working gas has substantiallyuniform flow across the regenerator 5408. Various embodiments of theregenerator 5408 are discussed in detail below, and in U.S. Pat. No.6,591,609, issued Jul. 17, 2003, to Kamen et al., and No. 6,862,883,issued Mar. 8, 2005, to Kamen et al., which are herein incorporated byreference in their entireties. When the working gas passes through thehot chamber 5404, a heater head 5410 may heat the gas causing the gas toexpand and push pistons 5202 and 5204 towards the cold chamber 5406,where the gas compresses. As the gas compresses in the cold chamber5406, pistons 5202 and 5204 may be guided back to the hot chamber toundergo the Stirling cycle again. The heater head 5410 may be a pin head(as shown in FIGS. 552A through 553B), a fin head (as shown in FIGS.556A through 556C), a folded fin head (as shown in FIGS. 556A through556C), heater tubes as shown in FIG. 54 (also shown as 2904 in FIG.529), or any other heater head embodiment known, including, but notlimited to, those described below. Various embodiments of heater head5410 are discussed in detail below, and in U.S. Pat. No. 6,381,958,issued May 7, 2002, to Kamen et al., No. 6,543,215, issued Apr. 8, 2003,to Langenfeld et al., No. 6,966,182, issued Nov. 22, 2005, to Kamen etal, and No. 7,308,787, issued Dec. 18, 2007, to LaRocque et al., whichare herein incorporated by reference in their entireties.

In some embodiments, a cooler 5412 may be positioned alongside cylinders5206 and 5208 to further cool the gas passing through to the coldchamber 5406. Various embodiments of cooler 5412 are discussed in detailin the proceeding sections, and in U.S. Pat. No. 7,325,399, issued Feb.5, 2008, to Strimling et al, which is herein incorporated by referencein its entirety.

In some embodiments, at least one piston seal 5414 may be positioned onpistons 5202 and 5204 to seal the hot section 5404 off from the coldsection 5406. Additionally, at least one piston guide ring 5416 may bepositioned on pistons 5202 and 5204 to help guide the pistons' motion intheir respective cylinders. Various embodiments of piston seal 5414 andguide ring 5416 are described in detail below, and in U.S. patentapplication Ser. No. 10/175,502, filed Jun. 19, 2002, published Feb. 6,2003 (now abandoned), which is herein incorporated by reference in itsentirety.

In some embodiments, at least one piston rod seal 5418 may be placedagainst piston rods 5224 and 5228 to prevent working gas from escapinginto the crankcase 5400, or alternatively into airlock space 5420. Thepiston rod seal 5418 may be an elastomer seal, or a spring-loaded seal.Various embodiments of the piston rod seal 5418 are discussed in detailbelow.

In some embodiments, the airlock space may be eliminated, for example,in the rolling diaphragm and/or bellows embodiments described in moredetail below. In those cases, the piston rod seals 5224 and 5228 sealthe working space from the crankcase.

In some embodiments, at least one rolling diaphragm/bellows 5422 may belocated along piston rods 5224 and 5228 to prevent airlock gas fromescaping into the crankcase 5400. Various embodiments of rollingdiaphragm 5422 are discussed in more detail below.

Although FIG. 54 shows a cross section of engine 5300 depicting only twopistons and one rocking beam drive, it is to be understood that theprinciples of operation described herein may apply to a four cylinder,double rocking beam drive engine, as designated generally by numeral5800 in FIG. 58.

Piston Operation

Referring now to FIGS. 58 and 511, FIG. 11 shows the operation ofpistons 5802, 5804, 5806, and 5808 during one revolution of crankshaft5814. With a ¼ revolution of crankshaft 5814, piston 5802 is at the topof its cylinder, otherwise known as top dead center, piston 5806 is inupward midstroke, piston 5804 is at the bottom of its cylinder,otherwise known as bottom dead center, and piston 5808 is in downwardmidstroke. With a ½ revolution of crankshaft 5814, piston 5802 is indownward midstroke, piston 5806 is at top dead center, piston 5804 is inupward midstroke, and piston 5808 is at bottom dead center. With ¾revolution of crankshaft 5814, piston 5802 is at bottom dead center,piston 5806 is in downward midstroke, piston 5804 is at top dead center,and piston 5808 is in upward midstroke. Finally, with a full revolutionof crankshaft 5814, piston 5802 is in upward midstroke, piston 5806 isat bottom dead center, piston 5804 is in downward midstroke, and piston5808 is at top dead center. During each ¼ revolution, there is a 90degree phase difference between pistons 5802 and 5806, a 180 degreephase difference between pistons 5802 and 5804, and a 270 degree phasedifference between pistons 5802 and 5808. FIG. 512A illustrates therelationship of the pistons being approximately 90 degrees out of phasewith the preceding and succeeding piston. Additionally, FIG. 511 showsthe exemplary embodiment machine means of transferring work. Thus, workis transferred from piston 5802 to piston 5806 to piston 5804 to piston5808 so that with a full revolution of crankshaft 5814, all pistons haveexerted work by moving from the top to the bottom of their respectivecylinders.

Referring now to FIG. 511, together with FIGS. 512A-512C, illustrate the90 degree phase difference between the pistons in the exemplaryembodiment. Referring now to FIG. 512A, although the cylinders are shownin a linear path, this is for illustration purposes only. In theexemplary embodiment of a four cylinder Stirling cycle machine, the flowpath of the working gas contained within the cylinder working spacefollows a figure eight pattern. Thus, the working spaces of cylinders51200, 51202, 51204, and 51206 are connected in a figure eight pattern,for example, from cylinder 51200 to cylinder 51202 to cylinder 51204 tocylinder 51208, the fluid flow pattern follows a figure eight. Stillreferring to FIG. 512A, an unwrapped view of cylinders 51200, 51202,51204, and 51206, taken along the line B-B (shown in FIG. 512C) isillustrated. The 90 degree phase difference between pistons as describedabove allows for the working gas in the warm section 51212 of cylinder51204 to be delivered to the cold section 51222 of cylinder 51206. Aspiston 5802 and 5808 are 90 degrees out of phase, the working gas in thewarm section 51214 of cylinder 51206 is delivered to the cold section51216 of cylinder 51200. As piston 5802 and piston 5806 are also 90degrees out of phase, the working gas in the warm section 51208 ofcylinder 51200 is delivered to the cold section 51218 of cylinder 51202.And as piston 5804 and piston 5806 are also 90 degrees out of phase, sothe working gas in the warm section 51210 of cylinder 51202 is deliveredto the cold section 51220 of cylinder 51204. Once the working gas of awarm section of a first cylinder enters the cold section of a secondcylinder, the working gas begins to compress, and the piston within thesecond cylinder, in its down stroke, thereafter forces the compressedworking gas back through a regenerator 51224 and heater head 51226(shown in FIG. 512B), and back into the warm section of the firstcylinder. Once inside the warm section of the first cylinder, the gasexpands and drives the piston within that cylinder downward, thuscausing the working gas within the cold section of that first cylinderto be driven through the preceding regenerator and heater head, and intothe cylinder. This cyclic transmigration characteristic of working gasbetween cylinders 51200, 51202, 51204, and 51206 is possible becausepistons 5802, 5804, 5806, and 5808 are connected, via drives 5810 and5812, to a common crankshaft 5814 (shown in FIG. 511), in such a waythat the cyclical movement of each piston is approximately 90 degrees inadvance of the movement of the proceeding piston, as depicted in FIG.512A.

Rolling Diaphragm, Metal Bellows, Airlock, and Pressure Regulator

In some embodiments of the Stirling cycle machine, lubricating fluid isused. To prevent the lubricating fluid from escaping the crankcase, aseal is used.

Referring now to FIGS. 513A-515, some embodiments of the Stirling cyclemachine include a fluid lubricated rocking beam drive that utilizes arolling diaphragm 51300 positioned along the piston rod 51302 to preventlubricating fluid from escaping the crankcase, not shown, but thecomponents that are housed in the crankcase are represented as 51304,and entering areas of the engine that may be damaged by the lubricatingfluid. It is beneficial to contain the lubricating fluid for iflubricating fluid enters the working space, not shown, but thecomponents that are housed in the working space are represented as51306, it would contaminate the working fluid, come into contact withthe regenerator 51308, and may clog the regenerator 51308. The rollingdiaphragm 51300 may be made of an elastomer material, such as rubber orrubber reinforced with woven fabric or non-woven fabric to providerigidity. The rolling diaphragm 51300 may alternatively be made of othermaterials, such as fluorosilicone or nitrile with woven fabric ornon-woven fabric. The rolling diaphragm 51300 may also be made of carbonnanotubes or chopped fabric, which is non-woven fabric with fibers ofpolyester or KEVLAR®, for example, dispersed in an elastomer. In thesome embodiments, the rolling diaphragm 51300 is supported by the topseal piston 51328 and the bottom seal piston 51310. In otherembodiments, the rolling diaphragm 51300 as shown in FIG. 13A issupported via notches in the top seal piston 51328.

In some embodiments, a pressure differential is placed across therolling diaphragm 51300 such that the pressure above the seal 51300 isdifferent from the pressure in the crankcase 51304. This pressuredifferential inflates seal 51300 and allows seal 51300 to act as adynamic seal as the pressure differential ensures that rolling diaphragmmaintains its form throughout operation. FIG. 513A, and FIGS. 513C-513Hillustrate how the pressure differential effects the rolling diaphragm.The pressure differential causes the rolling diaphragm 51300 to conformto the shape of the bottom seal piston 51310 as it moves with the pistonrod 51302, and prevents separation of the seal 51300 from a surface ofthe piston 51310 during operation. Such separation may cause sealfailure. The pressure differential causes the rolling diaphragm 51300 tomaintain constant contact with the bottom seal piston 51310 as it moveswith the piston rod 51302. This occurs because one side of the seal51300 will always have pressure exerted on it thereby inflating the seal51300 to conform to the surface of the bottom seal piston 51310. In someembodiments, the top seal piston 51328 ‘rolls over’ the corners of therolling diaphragm 51300 that are in contact with the bottom seal piston51310, so as to further maintain the seal 51300 in contact with thebottom seal piston 51310. In the exemplary embodiment, the pressuredifferential is in the range of 10 to 15 PSI. The smaller pressure inthe pressure differential is preferably in crankcase 51304, so that therolling diaphragm 51300 may be inflated into the crankcase 51304.However, in other embodiments, the pressure differential may have agreater or smaller range of value.

The pressure differential may be created by various methods including,but not limited to, the use of the following: a pressurized lubricationsystem, a pneumatic pump, sensors, an electric pump, by oscillating therocking beam to create a pressure rise in the crankcase 51304, bycreating an electrostatic charge on the rolling diaphragm 51300, orother similar methods. In some embodiments, the pressure differential iscreated by pressurizing the crankcase 51304 to a pressure that is belowthe mean pressure of the working space 51306. In some embodiments thecrankcase 51304 is pressurized to a pressure in the range of 10 to 15PSI below the mean pressure of the working space 51306, however, invarious other embodiments, the pressure differential may be smaller orgreater. Further detail regarding the rolling diaphragm is includedbelow.

Referring now to FIGS. 513C, 513G, and 513H, however, another embodimentof the Stirling machine is shown, wherein airlock space 51312 is locatedbetween working space 51306 and crankcase 51304. Airlock space 51312maintains a constant volume and pressure necessary to create thepressure differential necessary for the function of rolling diaphragm51300 as described above. In one embodiment, airlock 51312 is notabsolutely sealed off from working space 51306, so the pressure ofairlock 51312 is equal to the mean pressure of working space 51306.Thus, in some embodiments, the lack of an effective seal between theworking space and the crankcase contributes to the need for an airlockspace. Thus, the airlock space, in some embodiments, may be eliminatedby a more efficient and effective seal.

During operation, the working space 51306 mean pressure may vary so asto cause airlock 51312 mean pressure to vary as well. One reason thepressure may tend to vary is that during operation the working space mayget hotter, which in turn may increase the pressure in the workingspace, and consequently in the airlock as well since the airlock andworking space are in fluid communication. In such a case, the pressuredifferential between airlock 51312 and crankcase 51304 will also vary,thereby causing unnecessary stresses in rolling diaphragms 51300 thatmay lead to seal failure. Therefore, some embodiments of the machine,the mean pressure within airlock 51312 is regulated so as to maintain aconstant desired pressure differential between airlock 51312 andcrankcase 51304, and ensuring that rolling diaphragms 51300 stayinflated and maintains their form. In some embodiments, a pressuretransducer is used to monitor and manage the pressure differentialbetween the airlock and the crankcase, and regulate the pressureaccordingly so as to maintain a constant pressure differential betweenthe airlock and the crankcase. Various embodiments of the pressureregulator that may be used are described in further detail below, and inU.S. Pat. No. 7,310,945, issued Dec. 25, 2007, to Gurski et al., whichis herein incorporated by reference in its entirety.

A constant pressure differential between the airlock 51312 and crankcase51304 may be achieved by adding or removing working fluid from airlock51312 via a pump or a release valve. Alternatively, a constant pressuredifferential between airlock 51312 and crankcase 51304 may be achievedby adding or removing working fluid from crankcase 51304 via a pump or arelease valve. The pump and release valve may be controlled by thepressure regulator. Working fluid may be added to airlock 51312 (orcrankcase 51304) from a separate source, such as a working fluidcontainer, or may be transferred over from crankcase 51304. Shouldworking fluid be transferred from crankcase 51304 to airlock 51312, itmay be desirable to filter the working fluid before passing it intoairlock 51312 so as to prevent any lubricant from passing from crankcase51304 into airlock 51312, and ultimately into working space 51306, asthis may result in engine failure.

In some embodiments of the machine, crankcase 51304 may be charged witha fluid having different thermal properties than the working fluid. Forexample, where the working gas is helium or hydrogen, the crankcase maybe charged with argon. Thus, the crankcase is pressurized. In someembodiments, helium is used, but in other embodiments, any inert gas, asdescribed herein, may be used. Thus, the crankcase is a wet pressurizedcrankcase in the exemplary embodiment. In other embodiments where alubricating fluid is not used, the crankcase is not wet.

In the exemplary embodiments, rolling diaphragms 51300 do not allow gasor liquid to pass through them, which allows working space 51306 toremain dry and crankcase 51304 to be wet sumped with a lubricatingfluid. Allowing a wet sump crankcase 51304 increases the efficiency andlife of the engine as there is less friction in rocking beam drives51316. In some embodiments, the use of roller bearings or ball bearingsin drives 51316 may also be eliminated with the use of lubricating fluidand rolling diaphragms 51300. This may further reduce engine noise andincrease engine life and efficiency.

FIGS. 514A-514E show cross sections of various embodiments of therolling diaphragm (shown as 51400, 51410, 51412, 51422 and 51424)configured to be mounted between top seal piston and bottom seal piston(shown as 51328 and 51310 in FIGS. 513A and 513H), and between a topmounting surface and a bottom mounting surface (shown as 51320 and 51318in FIG. 513A). In some embodiments, the top mounting surface may be thesurface of an airlock or working space, and the bottom mounting surfacemay be the surface of a crankcase.

FIG. 514A shows one embodiment of the rolling diaphragm 51400, where therolling diaphragm 51400 includes a flat inner end 51402 that may bepositioned between a top seal piston and a bottom seal piston, so as toform a seal between the top seal piston and the bottom seal piston. Therolling diaphragm 51400 also includes a flat outer end 51404 that may bepositioned between a top mounting surface and a bottom mounting surface,so as to form a seal between the top mounting surface and the bottommounting surface. FIG. 514B shows another embodiment of the rollingdiaphragm, wherein rolling diaphragm 51410 may include a plurality ofbends 51408 leading up to flat inner end 51406 to provide for additionalsupport and sealing contact between the top seal piston and the bottomseal piston. FIG. 514C shows another embodiment of the rollingdiaphragm, wherein rolling diaphragm 51412 includes a plurality of bends51416 leading up to flat outer end 51414 to provide for additionalsupport and sealing contact between the top mounting surface and thebottom mounting surface.

FIG. 514D shows another embodiment of the rolling diaphragm whererolling diaphragm 51422 includes a bead along an inner end 51420thereof, so as to form an ‘o-ring’ type seal between a top seal pistonand a bottom seal piston, and a bead along an outer end 51418 thereof,so as to form an ‘o-ring’ type seal between a bottom mounting surfaceand a top mounting surface. FIG. 514E shows another embodiment of therolling diaphragm, wherein rolling diaphragm 51424 includes a pluralityof bends 51428 leading up to beaded inner end 51426 to provide foradditional support and sealing contact between the top seal piston andthe bottom seal piston. Rolling diaphragm 51424 may also include aplurality of bends 51430 leading up to beaded outer end 51432 to providefor additional support and sealing contact between the top seal pistonand the bottom seal piston.

Although FIGS. 514A through 514E depict various embodiments of therolling diaphragm, it is to be understood that rolling diaphragms may beheld in place by any other mechanical means known in the art.

Referring now to FIG. 515A, a cross section shows one embodiment of therolling diaphragm embodiment. A metal bellows 51500 is positioned alonga piston rod 51502 to seal off a crankcase (shown as 51304 in FIG. 513G)from a working space or airlock (shown as 51306 and 51312 in FIG. 513G).Metal bellows 51500 may be attached to a top seal piston 51504 and astationary mounting surface 51506. Alternatively, metal bellows 51500may be attached to a bottom seal piston (not shown), and a topstationary mounting surface. In one embodiment the bottom stationarymounting surface may be a crankcase surface or an inner airlock orworking space surface, and the top stationary mounting surface may be aninner crankcase surface, or an outer airlock or working space surface.Metal bellows 51500 may be attached by welding, brazing, or anymechanical means known in the art.

FIGS. 515B-515G depict a perspective cross sectional view of variousembodiments of the metal bellows, wherein the metal bellows is a weldedmetal bellows 51508. In some embodiments of the metal bellows, the metalbellows is preferably a micro-welded metal bellows. In some embodiments,the welded metal bellows 51508 includes a plurality of diaphragms 51510,which are welded to each other at either an inner end 51512 or an outerend 51514, as shown in FIGS. 515C and 515D. In some embodiments,diaphragms 51510 may be crescent shaped 51516, flat 51518, rippled51520, or any other shape known in the art.

Additionally, the metal bellows may alternatively be formed mechanicallyby means such as die forming, hydroforming, explosive hydroforming,hydramolding, or any other means known in the art.

The metal bellows may be made of any type of metal, including but notlimited to, steel, stainless steel, stainless steel 374, AM-350stainless steel, Inconel, Hastelloy, Haynes, titanium, or any otherhigh-strength, corrosion-resistant material.

In one embodiment, the metal bellows used are those available fromSenior Aerospace Metal Bellows Division, Sharon, Mass., or American BOA,Inc., Cumming, Ga.

Rolling Diaphragm and/or Bellows Embodiments

Various embodiments of the rolling diaphragm and/or bellows, whichfunction to seal, are described above. Further embodiments will beapparent to those of skill in the art based on the description above andthe additional description below relating to the parameters of therolling diaphragm and/or bellows.

In some embodiments, the pressure atop the rolling diaphragm or bellows,in the airlock space or airlock area (both terms are usedinterchangeably), is the mean-working-gas pressure for the machine,which, in some embodiments is an engine, while the pressure below therolling diaphragm and/or bellows, in the crankcase area, isambient/atmospheric pressure. In these embodiments, the rollingdiaphragm and/or bellows is required to operate with as much as 3000 psiacross it (and in some embodiments, up to 1500 psi or higher). In thiscase, the rolling diaphragm and/or bellows seal forms the working gas(helium, hydrogen, or otherwise) containment barrier for the machine(engine in the exemplary embodiment). Also, in these embodiments, theneed for a heavy, pressure-rated, structural vessel to contain thebottom end of the engine is eliminated, since it is now required tosimply contain lubricating fluid (oil is used as a lubricating fluid inthe exemplary embodiment) and air at ambient pressure, like aconventional internal combustion (“IC”) engine.

The capability to use a rolling diaphragm and/or bellows seal with suchan extreme pressure across it depends on the interaction of severalparameters. Referring now to FIG. 515H, an illustration of the actualload on the rolling diaphragm or bellows material is shown. As shown,the load is a function of the pressure differential and the annular gaparea for the installed rolling diaphragm or bellows seal.

Region 1 represents the portions of the rolling diaphragm and/or bellowsthat are in contact with the walls formed by the piston and cylinder.The load is essentially a tensile load in the axial direction, due tothe pressure differential across the rolling diaphragm and/or bellows.This tensile load due to the pressure across the rolling diaphragmand/or bellows can be expressed as:

L _(t) =P _(d) *A _(a)

Where

L_(t)=Tensile Load and

P_(d)=Pressure Differential

A_(a)=Annular Area

and

A _(a) =p/4*(D ² −d ²)

Where

D=Cylinder Bore and

d=Piston Diameter

The tensile component of stress in the bellows material can beapproximated as:

S _(t) =L _(t)/(p*(D+d)*t _(b))

Which reduces to:

S _(t) =P _(d)/4*(D−d)/tb

Later, we will show the relationship of radius of convolution, R_(c), toCylinder bore (D) and Piston Diameter (d) to be defined as:

R _(c)=(D−d)/4

So, this formula for St reduces to its final form:

S _(t) =P _(d) *R _(c) /t _(b)

Where

t_(b)=thickness of bellows material

Still referring to FIG. 515H, Region 2 represents the convolution. Asthe rolling diaphragm and/or bellows material turns the corner, in theconvolution, the hoop stress imposed on the rolling diaphragm and/orbellows material may be calculated. For the section of the bellowsforming the convolution, the hoop component of stress can be closelyapproximated as:

S _(h) =P _(d) *R _(c) /t _(b)

The annular gap that the rolling diaphragm and/or bellows rolls withinis generally referred to as the convolution area. The rolling diaphragmand/or bellows fatigue life is generally limited by the combined stressfrom both the tensile (and hoop) load, due to pressure differential, aswell as the fatigue due to the bending as the fabric rolls through theconvolution. The radius that the fabric takes on during this ‘rolling’is defined here as the radius of convolution, Rc.

R _(c)=(D−d)/4

The bending stress, Sb, in the rolling diaphragm and/or bellows materialas it rolls through the radius of convolution, Rc, is a function of thatradius, as well as the thickness of the materials in bending. For afiber-reinforced material, the stress in the fibers themselves (duringthe prescribed deflection in the exemplary embodiments) is reduced asthe fiber diameter decreases. The lower resultant stress for the samelevel of bending allows for an increased fatigue life limit. As thefiber diameter is further reduced, flexibility to decrease the radius ofconvolution Rc is achieved, while keeping the bending stress in thefiber under its endurance limit. At the same time, as Rc decreases, thetensile load on the fabric is reduced since there is less unsupportedarea in the annulus between the piston and cylinder. The smaller thefiber diameter, the smaller the minimum Rc, the smaller the annulararea, which results in a higher allowable pressure differential.

For bending around a prescribed radius, the bending moment isapproximated by:

M=E*1/R

Where:

M=Bending Moment

E=Elastic Modulus

=Moment of Inertia

R=Radius of Bend

Classical bending stress, S_(b), is calculated as:

S _(b) =M*Y/1

Where:

Y=Distance above neutral axis of bending

Substituting yields:

S _(b)=(E*1/R)*Y/1

S _(b) =E*Y/R

Assuming bending is about a central neutral axis:

Y _(max) =t _(b)/2

S _(b) =E*t _(b)/(2*R)

In some embodiments, rolling diaphragm and/or bellows designs for highcycle life are based on geometry where the bending stress imposed iskept about one order of magnitude less than the pressure-based loading(hoop and axial stresses). Based on the equation: Sb=E*tb/(2*R), it isclear that minimizing tb in direct proportion to Rc should not increasethe bending stress. The minimum thickness for the exemplary embodimentsof the rolling diaphragm and/or bellows material or membrane is directlyrelated to the minimum fiber diameter that is used in the reinforcementof the elastomer. The smaller the fibers used, the smaller resultant Rcfor a given stress level.

Another limiting component of load on the rolling diaphragm and/orbellows is the hoop stress in the convolution (which is theoreticallythe same in magnitude as the axial load while supported by the piston orcylinder). The governing equation for that load is as follows:

Sh=Pd*Rc/tb

Thus, if Rc is decreased in direct proportion to tb, then there is noincrease of stress on the membrane in this region. However, if thisratio is reduced in a manner that decreases Rc to a greater ratio thantb then parameters must be balanced. Thus, decreasing tb with respect toRc requires the rolling diaphragm and/or bellows to carry a heavierstress due to pressure, but makes for a reduced stress level due tobending. The pressure-based load is essentially constant, so this may befavorable—since the bending load is cyclic, therefore it is the bendingload component that ultimately limits fatigue life.

For bending stress reduction, tb ideally should be at a minimum, and Rcideally should be at a maximum. E ideally is also at a minimum. For hoopstress reduction, Rc ideally is small, and tb ideally is large.

Thus, the critical parameters for the rolling diaphragm and/or bellowsmembrane material are:

E, Elastic Modulus of the membrane material;

tb, membrane thickness (and/or fiber diameter);

Sut, Ultimate tensile strength of the rolling diaphragm and/or bellows;and

Slcf, The limiting fatigue strength of the rolling diaphragm and/orbellows.

Thus, from E, tb and Sut, the minimum acceptable Rc may be calculated.Next, using Rc, Slcf, and tb, the maximum Pd may be calculates. Rc maybe adjusted to shift the bias of load (stress) components between thesteady state pressure stress and the cyclic bending stress. Thus, theideal rolling diaphragm and/or bellows material is extremely thin,extremely strong in tension, and very limber in flexion.

Thus, in some embodiments, the rolling diaphragm and/or bellows material(sometimes referred to as a “membrane”), is made from carbon fibernanotubes. However, additional small fiber materials may also be used,including, but not limited to nanotube fibers that have been braided,nanotube untwisted yarn fibers, or any other conventional materials,including but not limited to KEVLAR, glass, polyester, synthetic fibersand any other material or fiber having a desirable diameter and/or otherdesired parameters as described in detail above.

Piston Seals and Piston Rod Seals

Referring now to FIG. 513G, an embodiment of the machine is shownwherein an engine 51326, such as a Stirling cycle engine, includes atleast one piston rod seal 51314, a piston seal 51324, and a piston guidering 51322, (shown as 51616 in FIG. 516). Various embodiments of thepiston seal 51324 and the piston guide ring 51322 are further discussedbelow, and in U.S. Patent Application Publication No. US 2003/0024387 AIto Langenfeld et al., Feb. 6, 2003 (now abandoned), which, as mentionedbefore, is incorporated by reference.

FIG. 516 shows a partial cross section of the piston 51600, driven alongthe central axis 51602 of cylinder, or the cylinder 51604. The pistonseal (shown as 51324 in FIG. 513G) may include a seal ring 51606, whichprovides a seal against the contact surface 51608 of the cylinder 51604.The contact surface 51608 is typically a hardened metal (preferably58-62 RC) with a surface finish of 12 RMS or smoother. The contactsurface 51608 may be metal which has been case hardened, such as 8260hardened steel, which may be easily case hardened and may be groundand/or honed to achieve a desired finish. The piston seal may alsoinclude a backing ring 51610, which is sprung to provide a thrust forceagainst the seal ring 51606 thereby providing sufficient contactpressure to ensure sealing around the entire outward surface of the sealring 51606. The seal ring 51606 and the backing ring 51610 may togetherbe referred to as a piston seal composite ring. In some embodiments, theat least one piston seal may seal off a warm portion of cylinder 51604from a cold portion of cylinder 51604.

Referring now to FIG. 517, some embodiments include a piston rod seal(shown as 51314 in FIG. 513G) mounted in the piston rod cylinder wall51700, which, in some embodiments, may include a seal ring 51706, whichprovides a seal against the contact surface 51708 of the piston rod51604 (shown as 51302 in FIG. 513G). The contact surface 51708 in someembodiments is a hardened metal (preferably 58-62 RC) with a surfacefinish of 12 RMS or smoother. The contact surface 51708 may be metalwhich has been case hardened, such as 58260 hardened steel, which may beeasily case hardened and may be ground and/or honed to achieve a desiredfinish. The piston seal may also include a backing ring 51710, which issprung to provide a radial or hoop force against the seal ring 51706thereby providing sufficient contact hoop stress to ensure sealingaround the entire inward surface of seal ring 51706. The seal ring 51706and the backing ring 51710 may together be referred to as a piston rodseal composite ring.

In some embodiments, the seal ring and the backing ring may bepositioned on a piston rod, with the backing exerting an outwardpressure on the seal ring, and the seal ring may come into contact witha piston rod cylinder wall 51702. These embodiments require a largerpiston rod cylinder length than the previous embodiment. This is becausethe contact surface on the piston rod cylinder wall 51702 will be longerthan in the previous embodiment, where the contact surface 51708 lies onthe piston rod itself. In yet another embodiment, piston rod seals maybe any functional seal known in the art including, but not limited to,an o-ring, a graphite clearance seal, graphite piston in a glasscylinder, or any air pot, or a spring energized lip seal. In someembodiments, anything having a close clearance may be used, in otherembodiments, anything having interference, for example, a seal, is used.In the exemplary embodiment, a spring energized lip seal is used. Anyspring energized lip seal may be used, including those made by BAL SEALEngineering, Inc., Foothill Ranch, Calif. In some embodiments, the sealused is a BAL SEAL Part Number X558604.

The material of the seal rings 51606 and 51706 is chosen by consideringa balance between the coefficient of friction of the seal rings 51606and 51706 against the contact surfaces 51608 and 51708, respectively,and the wear on the seal rings 51606 and 51706 it engenders. Inapplications in which piston lubrication is not possible, such as at thehigh operating temperatures of a Stirling cycle engine, the use ofengineering plastic rings is used. The embodiments of the compositioninclude a nylon matrix loaded with a lubricating and wear-resistantmaterial. Examples of such lubricating materials include PTFE/silicone,PTFE, graphite, etc. Examples of wear-resistant materials include glassfibers and carbon fibers. Examples of such engineering plastics aremanufactured by LNP Engineering Plastics, Inc. of Exton, Pa. Backingrings 51610 and 51710 is preferably metal.

The fit between the seal rings 51606 and 51706 and the seal ring grooves51612 and 51712, respectively, is preferably a clearance fit (about0.002″), while the fit of the backing rings 51610 and 51710 ispreferably a looser fit, of the order of about 0.005″ in someembodiments. The seal rings 51606 and 51706 provide a pressure sealagainst the contact surfaces 51608 and 51708, respectively, and also oneof the surfaces 51614 and 51714 of the seal ring grooves 51612 and51712, respectively, depending on the direction of the pressuredifference across the rings 51606 and 51706 and the direction of thepiston 51600 or the piston rod 51704 travel.

FIGS. 518A and 518B show that if the backing ring 51820 is essentiallycircularly symmetrical, but for the gap 51800, it will assume, uponcompression, an oval shape, as shown by the dashed backing ring 51802.The result may be an uneven radial or hoop force (depicted by arrows51804) exerted on the seal ring (not shown, shown as 51606 and 51706 inFIGS. 516 and 517), and thus an uneven pressure of the seal ringsagainst the contact surfaces (not shown, shown as 51608 and 51708 inFIGS. 516 and 517) respectively, causing uneven wear of the seal ringsand in some cases, failure of the seals.

A solution to the problem of uneven radial or hoop force exerted by thepiston seal backing ring 51820, in accordance with an embodiment, is abacking ring 51822 having a cross-section varying with circumferentialdisplacement from the gap 51800, as shown in FIGS. 518C and 518D. Atapering of the width of the backing ring 51822 is shown from theposition denoted by numeral 51806 to the position denoted by numeral51808. Also shown in FIGS. 518C and 518D is a lap joint 51810 providingfor circumferential closure of the seal ring 51606. As some seals willwear significantly over their lifetime, the backing ring 51822 shouldprovide an even pressure (depicted by numeral 51904 in FIG. 519B) of arange of movement. The tapered backing ring 51822 shown in FIGS. 518Cand 518D may provide this advantage.

FIGS. 519A and 519B illustrate another solution to the problem of unevenradial or hoop force of the piston seal ring against the pistoncylinder, in accordance with some embodiments. As shown in FIG. 519A,backing ring 51910 is fashioned in an oval shape, so that uponcompression within the cylinder, the ring assumes the circular shapeshown by dashed backing ring 51902. A constant contact pressure betweenthe seal ring and the cylinder contact surface may thus be provided byan even radial force 51904 of backing ring 51902, as shown in FIG. 519B.

A solution to the problem of uneven radial or hoop force exerted by thepiston rod seal backing ring, in accordance with some embodiments, is abacking ring 51824 having a cross-section varying with circumferentialdisplacement from gap 51812, as shown in FIGS. 518E and 518F. A taperingof the width of backing ring 51824 is shown from the position denoted bynumeral 51814 to the position denoted by numeral 51816. Also shown inFIGS. 518E and 518F is a lap joint 51818 providing for circumferentialclosure of seal ring 51706. As some seals will wear significantly overtheir lifetime, backing ring 51824 should provide an even pressure(depicted by numeral 52004 in FIG. 520B) of a range of movement. Thetapered backing ring 51824 shown in FIGS. 518E and 518F may provide thisadvantage.

FIGS. 520A and 520B illustrate another solution to the problem of unevenradial or hoop force of the piston rod seal ring against the piston rodcontact surface, in accordance with some embodiments. As shown in FIG.520A, backing ring (shown by dashed backing ring 52000) is fashioned asan oval shape, so that upon expansion within the cylinder, the ringassumes the circular shape shown by backing ring 52002. A constantcontact pressure between the seal ring 51706 and the cylinder contactsurface may thus be provided by an even radial thrust force 52004 ofbacking ring 52002, as shown in FIG. 520B.

Referring again to FIG. 516, at least one guide ring 51616 may also beprovided, in accordance with some embodiments, for bearing any side loadon piston 51600 as it moves up and down the cylinder 51604. Guide ring51616 is also preferably fabricated from an engineering plastic materialloaded with a lubricating material. A perspective view of guide ring51616 is shown in FIG. 521. An overlapping joint 52100 is shown and maybe diagonal to the central axis of guide ring 51616.

Lubricating Fluid Pump and Lubricating Fluid Passageways

Referring now to FIG. 522, a representative illustration of oneembodiment of the engine 52200 for the machine is shown having a rockingbeam drive 52202 and lubricating fluid 52204. In some embodiments, thelubricating fluid is oil. The lubricating fluid is used to lubricateengine parts in the crankcase 52206, such as hydrodynamic pressure fedlubricated bearings. Lubricating the moving parts of the engine 52200serves to further reduce friction between engine parts and furtherincrease engine efficiency and engine life. In some embodiments,lubricating fluid may be placed at the bottom of the engine, also knownas an oil sump, and distributed throughout the crankcase. Thelubricating fluid may be distributed to the different parts of theengine 52200 by way of a lubricating fluid pump, wherein the lubricatingfluid pump may collect lubricating fluid from the sump via a filteredinlet. In the exemplary embodiment, the lubricating fluid is oil andthus, the lubricating fluid pump is herein referred to as an oil pump.However, the term “oil pump” is used only to describe the exemplaryembodiment and other embodiments where oil is used as a lubricatingfluid, and the term shall not be construed to limit the lubricatingfluid or the lubricating fluid pump.

Referring now to FIGS. 523A and 523B, one embodiment of the engine isshown, wherein lubricating fluid is distributed to different parts ofthe engine 52200 that are located in the crankcase 52206 by a mechanicaloil pump 52208. The oil pump 52208 may include a drive gear 52210 and anidle gear 52212. In some embodiments, the mechanical oil pump 52208 maybe driven by a pump drive assembly. The pump drive assembly may includea drive shaft 52214 coupled to a drive gear 52210, wherein the driveshaft 52214 includes an intermediate gear 52216 thereon. Theintermediate gear 52216 is preferably driven by a crankshaft gear 52220,wherein the crankshaft gear 52220 is coupled to the primary crankshaft52218 of the engine 52200, as shown in FIG. 524. In this configuration,the crankshaft 52218 indirectly drives the mechanical oil pump 52208 viathe crankshaft gear 52220, which drives the intermediate gear 52216 onthe drive shaft 52214, which, in turn, drives the drive gear 52210 ofthe oil pump 52208.

The crankshaft gear 52220 may be positioned between the crankpins 52222and 52224 of crankshaft 52218 in some embodiments, as shown in FIG. 24.In other embodiments, the crankshaft gear 52220 may be placed at an endof the crankshaft 52218, as shown in FIGS. 525A-525C.

For ease of manufacturing, the crankshaft 52218 may be composed of aplurality of pieces. In these embodiments, the crankshaft gear 52220 maybe to be inserted between the crankshaft pieces during assembly of thecrankshaft.

The drive shaft 52214, in some embodiments, may be positionedperpendicularly to the crankshaft 52218, as shown in FIGS. 523A and525A. However, in some embodiments, the drive shaft 52214 may bepositioned parallel to the crankshaft 52218, as shown in FIGS. 525B and525C.

In some embodiments, the crankshaft gear 52234 and the intermediate gear52232 may be sprockets, wherein the crankshaft gear 52234 and theintermediate gear 52232 are coupled by a chain 52226, as shown in FIGS.525C and 526C. In such an embodiments, the chain 52226 is used to drivea chain drive pump (shown as 52600 in FIGS. 526A through 526C).

In some embodiments, the gear ratio between the crankshaft 52218 and thedrive shaft 52214 remains constant throughout operation. In such anembodiment, it is important to have an appropriate gear ratio betweenthe crankshaft and the drive shaft, such that the gear ratio balancesthe pump speed and the speed of the engine. This achieves a specifiedflow of lubricant required by a particular engine RPM (revolutions perminute) operating range.

In some embodiments, lubricating fluid is distributed to different partsof an engine by an electric pump. The electric pump eliminates the needfor a pump drive assembly, which is otherwise required by a mechanicaloil pump.

Referring back to FIGS. 523A and 523B, the oil pump 52208 may include aninlet 52228 to collect lubricating fluid from the sump and an outlet52230 to deliver lubricating fluid to the various parts of the engine.In some embodiments, the rotation of the drive gear 52212 and the idlegear 52210 cause the lubricating fluid from the sump to be drawn intothe oil pump through the inlet 52228 and forced out of the pump throughthe outlet 52230. The inlet 52228 preferably includes a filter to removeparticulates that may be found in the lubricating fluid prior to itsbeing drawn into the oil pump. In some embodiments, the inlet 52228 maybe connected to the sump via a tube, pipe, or hose. In some embodiments,the inlet 52228 may be in direct fluid communication with the sump.

In some embodiments, the oil pump outlet 52230 is connected to a seriesof passageways in the various engine parts, through which thelubricating fluid is delivered to the various engine parts. The outlet52230 may be integrated with the passageways so as to be in directcommunication with the passageways, or may be connected to thepassageways via a hose or tube, or a plurality of hoses or tubes. Theseries of passageways are preferably an interconnected network ofpassageways, so that the outlet 52230 may be connected to a singlepassageway inlet and still be able to deliver lubricating fluid to theengine's lubricated parts.\

FIGS. 527A-527D show one embodiments, wherein the oil pump outlet (shownas 52230 in FIG. 523B) is connected to a passageway 52700 in the rockershaft 52702 of the rocking beam drive 52704. The rocker shaft passageway52700 delivers lubricating fluid to the rocker pivot bearings 52706, andis connected to and delivers lubricating fluid to the rocking beampassageways (not shown). The rocking beam passageways deliverlubricating fluid to the connecting wrist pin bearings 52708, the linkrod bearings 52710, and the link rod passageways 52712. The link rodpassageways 52712 deliver lubricating fluid to the piston rod couplingbearing 52714. The connecting rod passageway (not shown) of theconnecting rod 52720 delivers lubricating fluid to a first crank pin52722 and the crankshaft passageway 52724 of the crankshaft 52726. Thecrankshaft passageway 52724 delivers lubricating fluid to the crankshaftjournal bearings 52728, the second crank pin bearing 52730, and thespline shaft passageway 52732. The spline shaft passageway 52732delivers lubricating fluid to the spline shaft spline joints 52734 and52736. The oil pump outlet (not shown, shown in FIG. 523B as 52230) insome embodiments is connected to the main feed 52740. In someembodiments, an oil pump outlet may also be connected to and providelubricating fluid to the coupling joint linear bearings 52738. In someembodiments, an oil pump outlet may be connected to the linear bearings52738 via a tube or hose, or plurality of tubes or hoses. Alternatively,the link rod passageways 52712 may deliver lubricating fluid to thelinear bearings 52738.

Thus, the main feed 52740 delivers lubricating fluid to the journalbearings surfaces 52728. From the journal bearing surfaces 52728, thelubricating fluid is delivered to the crankshaft main passage. Thecrankshaft main passage delivers lubricating fluid to both the splineshaft passageway 52732 and the connecting rod bearing on the crank pin52724.

Lubricating fluid is delivered back to the sump, preferably by flowingout of the aforementioned bearings and into the sump. In the sump, thelubricating fluid will be collected by the oil pump and redistributedthroughout the engine.

Distribution

As described above, various embodiments of the system, methods andapparatus may advantageously provide a low-cost, easily maintained,highly efficient, portable, and failsafe system that can provide areliable source of drinking water for use in all environments regardlessof initial water quality. The system is intended to produce a continuousstream of potable water, for drinking or medical applications, forexample, on a personal or limited community scale using a portable powersource and moderate power budget. As an example, in some embodiment, thewater vapor distillation apparatus may be utilized to produce at leastapproximately 10 gallons of water per hour on a power budget ofapproximately 500 watts. This may be achieved through a very efficientheat transfer process and a number of sub-system design optimizations.

The various embodiments of the water vapor distillation apparatus may bepowered by a battery, electricity source or by a generator, as describedherein. The battery may be a stand alone battery or could be connectedto a motor transport apparatus, such as a scooter, any other motorvehicle, which some cases may be a hybrid motor vehicle or a batterypowered vehicle.

In one embodiment, the system may be used in the developing world or ina remote village or remote living quarters. The system is especiallyadvantageous in communities with any one or more of the following, forexample (but not by limitation): unsafe water of any kind at any time,little to no water technical expertise for installation, unreliableaccess to replacement supplies, limited access to maintenance anddifficult operating environment.

The system acts to purify any input source and transform the inputsource to high-quality output, i.e., cleaner water. In some applicationsthe water vapor distillation apparatus may be in a community that doesnot have any municipal infrastructure to provide source water. Thus, inthese situations an embodiment of the water vapor distillation apparatusmay be capable of accepting source water having varying qualities ofpurity.

The system is also easy to install and operate. The water vapordistillation apparatus is designed to be an autonomous system. Thisapparatus may operate independently without having to be monitored byoperators. This is important because, in many of the locations where thewater vapor distillation apparatus may be installed and or utilized,mechanics may be rare or unreliable.

The system has minimal maintenance requirement. In the exemplaryembodiments, the system does not require any consumables and/ordisposables, thus, the system itself may be utilized for a period oftime absent replacing any elements or parts. This is important becausein many applications the water vapor distillation apparatus may belocated in a community that lacks people having technical expertise tomaintain mechanical devices such as the water vapor distillationapparatus. The system is also inexpensive, making it an option for anycommunity.

In addition, the water vapor distillation apparatus may be used in anycommunity where clean drinking water is not readily or sufficientlyavailable. For example, communities that have both a utility to provideelectricity to operate the water vapor distillation device and municipalwater to supply the apparatus.

Thus, the water vapor distillation apparatus may be used in communitiesthat may have a utility grid for supply electricity but no cleandrinking water. Conversely, the community may have municipal water thatis not safe and no utility grid to supply electricity. In theseapplications, the water vapor distillation apparatus may be poweredusing devices including, but not limited to a Stirling engine, aninternal combustion engine, a generator, batteries or solar panels.Sources of water may include but are not limited to local streams,rivers, lakes, ponds, or wells, as well as, the ocean.

In communities that have no infrastructure the challenge is to locate awater source and be able to supply power to operate the water vapordistillation apparatus. As previously discussed, the water vapordistillation apparatus may be power using several types of devices.

In this type of situation one likely place to install a water vapordistillation apparatus may be in the community clinic or health centers.These places typically have some form of power source and are accessibleto the most members of the community.

Again, as described herein, sources of electricity may include aStirling engine. This type of engine is well suited for application inthe water machine because the engine provides a sufficient amount ofelectrical power to operate the machine without significantly affectingthe size of the machine.

The water vapor distillation apparatus may supply approximately between50 and 250 people per day with water. In the exemplary embodiment, theoutput is 30 liters per hour. This production rate is suitable for asmall village or community's needs. The energy needs includeapproximately 900 Watts. Thus, the energy requirements are minimal topower the water vapor distillation apparatus. This low power requirementis suitable to a small/remote village or community. Also, in someembodiments, a standard outlet is suitable as the electrical source. Theweight of the water vapor distillation apparatus is approximately 90 Kg,in the exemplary embodiment, and the size (H×D×W)−160 cm×50 cm×50 cm.

Knowledge of operating temperatures, TDS, and fluid flows providesinformation to allow production of potable water under a wide range ofambient temperatures, pressures, and dissolved solid content of thesource water. One particular embodiment may utilize a control methodwhereby such measurements (T, P, TDS, flow rates, etc) are used inconjunction with a simple algorithm and look-up table allowing anoperator or computer controller to set operating parameters for optimumperformance under existing ambient conditions.

In some embodiments, the apparatus may be incorporated as part of asystem for distributing water. Within this system may include amonitoring system. This monitoring system may include, but is notlimited to having an input sensor for measuring one or morecharacteristics of the input to the generation device and an outputsensor for measuring consumption or other characteristic of output fromthe generation device. The monitoring system may have a controller forconcatenating measured input and consumption of output on the basis ofthe input and output sensors.

Where the generation device of a particular utility of a network is awater vapor distillation apparatus, the input sensor may be a flow ratemonitor. Moreover, the output sensor may be a water quality sensorincluding one or more of torpidity, conductivity, and temperaturesensors.

The monitoring system may also have a telemetry module for communicatingmeasured input and output parameters to a remote site, either directlyor via an intermediary device such as a satellite, and, moreover, thesystem may include a remote actuator for varying operating parameters ofthe generator based on remotely received instructions. The monitoringsystem may also have a self-locating device, such as a GPS receiver,having an output indicative of the location of the monitoring system. Inthat case, characteristics of the measured input and output may dependupon the location of the monitoring system.

The monitoring system described above may be included within adistributed network of utilities providing sources of purified water.The distributed network has devices for generating water using inputsensors for measuring inputs to respective generators, output sensor formeasuring consumption of output from respective generators, and atelemetry transmitter for transmitting input and output parameters of aspecified generator. Finally, the distributed network may have a remoteprocessor for receiving input and output parameters from a plurality ofutility generators.

Referring now to FIG. 42, this figure depicts monitoring generationdevice 4202. Generation device 4202 may be a water vapor distillationapparatus as disclosed herein. Generation device 4202 may typically becharacterized by a set of parameters that describe its current operatingstatus and conditions. Such parameters may include, without limitation,its temperature, its input or output flux, etc., and may be subject tomonitoring by means of sensors, as described in detail below.

Still referring to FIG. 42, source water enters the generation device4202 at inlet 4204 and leaves the generation device at outlet 4206. Theamount of source water 4208 entering generation device 4202 and theamount of purified water 4210 leaving generation device 4202 may bemonitored through the use of one or more of a variety of sensorscommonly used to determine flow rate, such as sensors for determiningthem temperature and pressure or a rotometer, located at inlet sensormodule 4212 and/or at outlet sensor module 4214, either on a per eventor cumulative basis. Additionally, the proper functioning of thegeneration device 4202 may be determined by measuring the turbidity,conductivity, and/or temperature at the outlet sensor module 4214 and/orthe inlet sensor module 4212. Other parameters, such as system usagetime or power consumption, either per event or cumulatively, may also bedetermined. A sensor may be coupled to an alarm or shut off switch thatmay be triggered when the sensor detects a value outside apre-programmed range.

When the location of the system is known, either through direct input ofthe system location or by the use of a GPS location detector, additionalwater quality tests may be run based on location, including checks forknown local water contaminates, utilizing a variety of detectors, suchas antibody chip detectors or cell-based detectors. The water qualitysensors may detect an amount of contaminates in water. The sensors maybe programmed to sound an alarm if the water quality value rises above apre-programmed water quality value. The water quality value is themeasured amount of contaminates in the water. Alternatively, a shut offswitch may turn off the generation device if the water quality valuerises about a pre-programmed water quality value.

Further, scale build-up in the generation device 4202, if any, may bedetermined by a variety of methods, including monitoring the heattransfer properties of the system or measuring the flow impedance. Avariety of other sensors may be used to monitor a variety of othersystem parameters.

Still referring to FIG. 42, the sensors described above may be used tomonitor and/or record the various parameters described above onboard thegeneration device 4202, or in an alternative embodiment the generationdevice 4202 may be equipped with a communication system 4214, such as acellular communication system. The communication system 4214 could be aninternal system used solely for communication between the generationdevice 4202 and the monitoring station 4216. Alternatively, thecommunication system 4214 could be a cellular communication system thatincludes a cellular telephone for general communication through acellular satellite system 4218. The communication system 4214 may alsoemploy wireless technology such as the Bluetooth open specification. Thecommunication system 4214 may additionally include a GPS (GlobalPositioning System) locator.

Still referring to FIG. 42, the communication system 4214 enables avariety of improvements to the generation device 4202, by enablingcommunication with a monitoring station 4216. For example, themonitoring station 4216 may monitor the location of the generationdevice 4202 to ensure that use in an intended location by an intendeduser. Additionally, the monitoring station 4216 may monitor the amountof water and/or electricity produced, which may allow the calculation ofusage charges. Additionally, the determination of the amount of waterand/or electricity produced during a certain period or the cumulativehours of usage during a certain period, allows for the calculation of apreventative maintenance schedule. If it is determined that amaintenance call is required, either by the calculation of usage or bythe output of any of the sensors used to determine water quality, themonitoring station 4216 may arrange for a maintenance visit. In the casethat a GPS (Global Positioning System) locator is in use, monitoringstation 4216 may determine the precise location of the generation device4202 to better facilitate a maintenance visit. The monitoring station4216 may also determine which water quality or other tests are mostappropriate for the present location of the generation device 4202. Thecommunication system 4214 may also be used to turn the generation device4202 on or off, to pre-heat the device prior to use, or to deactivatethe system in the event the system is relocated without advance warning,such as in the event of theft.

Now referring to FIG. 43, the use of the monitoring and communicationsystem described above facilitates the use of a variety of utilitydistribution systems. An organization 43, such as a Government agency,non-governmental agency (NGO), or privately funded relief organization,a corporation, or a combination of these, could provide distributedutilities, such as safe drinking water or electricity, to a geographicalor political area, such as an entire country. The organization 43 maythen establish local distributors 44A, 44B, and 44C. These localdistributors could preferably be a monitoring station 4216 (See FIG. 42)previously described. In one possible arrangement, organization 43 couldprovide some number of generation devices 4202 (See FIG. 42) to thelocal distributor 44, etc. In another possible arrangement, theorganization 43 could sell, loan, or make other financial arrangementsfor the distribution of the generation devices 4202 (See FIG. 42). Thelocal distributor 44, etc. could then either give these generationdevices to operators 45, etc., or provide the generation devices 4202(See FIG. 42) to the operators though some type of financialarrangement, such as a sale or micro-loan.

Still referring to FIG. 43, the operator 45 could then providedistributed utilities to a village center, school, hospital, or othergroup at or near the point of water access. In one exemplary embodiment,when the generation device 4202 (See FIG. 42) is provided to theoperator 45 by means of a micro-loan, the operator 45 could charge theend users on a per-unit bases, such as per watt hour in the case ofelectricity or per liter in the case of purified water. Either the localdistributor 44 or the organization 43 may monitor usage and otherparameters using one of the communication systems described above. Thedistributor 44 or the organization 43 could then recoup some of the costof the generation device 45 (See FIG. 42) or effect repayment of themicro-loan by charging the operator 4312 for some portion of theper-unit charges, such as 50%. The communication systems describedadditionally may be used to deactivate the generation device 4202 (SeeFIG. 42) if the generation device is relocated outside of a pre-set areaor if payments are not made in a timely manner. This type of adistribution system may allow the distribution of needed utilitiesacross a significant area quickly, while then allowing for at least thepartial recoupment of funds, which, for example, could then be used todevelop a similar system in another area.

Now referring to FIG. 44, this figure illustrates a conceptual flowdiagram of one possible way to incorporate an alternate embodiment ofthe water vapor distillation apparatus into a system. In an embodimentof this type, fluid flows through the system from an intake 4404 into anexchanger 4406 wherein exchanger 4406 receives heat from at least one ofa plurality of sources including a condenser 4402, a head 4408, andexhaust (not shown) from a power source such as an internal or externalcombustion engine. Fluid continues flowing past heat exchanger 4406 intoa sump 4410 and into a core 4412 in thermal contact with condenser 4402.In the core 4412, the fluid is partially vaporized. From core 4412, thevapor path proceeds into head 4408 in communication with a compressor4414, and from there into condenser 4402. After the vapor has condensed,fluid proceeds from condenser 4402 through heat exchanger 4406, andfinally into an exhaust region 4416 and then out as final distilledproduct.

Referring to FIGS. 44 and 44A, a power source 4418 may be used to powerthe overall system. Power source 4418 may be coupled to a motor (notshown) that is used to drive compressor 4414, particularly whencompressor 4414 is a steam pump, such as a liquid ring pump or aregenerative blower. The power source 4418 may also be used to provideelectrical energy to the other elements of the apparatus shown in FIG.44. Power source 4418 may be, for example, an electrical outlet, astandard internal combustion (IC) generator or an external combustiongenerator. In one exemplary embodiment, the power source is a Stirlingcycle engine. An IC generator and an external combustion generatoradvantageously produce both power and thermal energy as shown in FIG.44A, where engine 4420 produces both mechanical and thermal energy.Engine 4420 may be either an internal combustion engine or an externalcombustion engine. A generator 4422, such as a permanent magnetbrushless motor, is coupled to a crankshaft of the engine 4420 andconverts the mechanical energy produced by the engine 4420 to electricalenergy, such as power 4424. Engine 4420 also produces exhaust gases 4426and heat 4428. The thermal energy produced by the engine 4420 in theform of exhaust gas 4426 and heat 4428 may be advantageously used toprovide heat to the system.

Referring to FIG. 44, heat from a power source 4418 may be recaptured bychanneling the exhaust into the insulated cavity that surrounds theapparatus, which may lie between external housing and the individualapparatus components. In one embodiment, exhaust may blow across afinned heat exchanger that heats source fluid prior to entering theevaporator/condenser 4402. In other embodiments, the source fluid flowspast a tube-in-tube heat exchanger as described above with reference tothe exemplary embodiment.

Referring now to FIG. 528A, one embodiment of the system is shown. Thesystem includes two basic functional components that may be combinedwithin a single integral unit or may be capable of separate operationand coupled as described herein for the purpose of local waterpurification. FIG. 528A depicts an of the system in which a power unit528010 is coupled electrically, via cable 528014, to provide electricalpower to a water vapor distillation apparatus 528012, with exhaust gasfrom the power unit 528010 coupled to convey heat to the waterdistillation unit 528012 via an exhaust duct 528016.

In the exemplary embodiment, the power unit 528010 is a Stirling cycleengine. The Stirling cycle engine may be any of the embodimentsdescribed herein. Thermal cycle engines are limited, by second law ofthermodynamics, to a fractional efficiency, i.e., a Carnot efficiency of(TH−TC)/TH, where TH and TC are the temperatures of the available heatsource and ambient thermal background, respectively. During thecompression phase of a heat engine cycle, heat must be exhausted fromthe system in a manner not entirely reversible, thus there will alwaysbe a surfeit of exhaust heat. More significantly, moreover, not all theheat provided during the expansion phase of the heat engine cycle iscoupled into the working fluid. Here, too, exhaust heat is generatedthat may be used advantageously for other purposes. The total heatthermodynamically available (i.e., in gas hotter than the ambientenvironment) in the burner exhaust is typically on the order of 10% ofthe total input power. For a power unit delivering on the order of akilowatt of electrical power, as much as 700 W of heat may be availablein an exhaust stream of gas at temperatures in the vicinity of 200° C.In accordance with embodiments of the present apparatus, system andmethods, the exhaust heat, as well as the electrical power generated byan engine-powered generator, are used in the purification of water forhuman consumption, thereby advantageously providing an integrated systemto which only raw water and a fuel need be provided.

Moreover, external combustion engines, such as Stirling cycle engines,are capable of providing high thermal efficiency and low emission ofpollutants, when such methods are employed as efficient pumping ofoxidant (typically, air, and, referred to herein and in any appendedclaims, without limitation, as “air”) through the burner to providecombustion, and the recovery of hot exhaust leaving the heater head. Inmany applications, air is pre-heated, prior to combustion, nearly to thetemperature of the heater head, so as to achieve the stated objectivesof thermal efficiency. However, the high temperature of preheated air,desirable for achieving high thermal efficiency, complicates achievinglow-emission goals by making it difficult to premix the fuel and air andby requiring large amounts of excess air in order to limit the flametemperature. Technology directed toward overcoming these difficulties inorder to achieve efficient and low-emission operation of thermal enginesis described, for example, in U.S. Pat. No. 6,062,023 (Kerwin, et al.)issued May 16, 2000, and incorporated herein by reference.

External combustion engines are, additionally, conducive to the use of awide variety of fuels, including those most available under particularlocal circumstances; however the teachings of the present descriptionare not limited to such engines, and internal combustion engines arealso within the scope of the current disclosure. Internal combustionengines, however, impose difficulties due to the typically pollutednature of the exhausted gases, and external combustion engines arepreferably employed.

Still referring to FIG. 528A, an embodiment of a power unit 528010 isshown schematically in FIG. 528B. Power unit 528010 includes an externalcombustion engine 528101 coupled to a generator 528102. In an exemplaryembodiment, the external combustion engine 528101 is a Stirling cycleengine. The outputs of the Stirling cycle engine 528101 during operationinclude both mechanical energy and residual heat energy. Heat producedin the combustion of a fuel in a burner 528104 is applied as an input tothe Stirling cycle engine 528101, and partially converted to mechanicalenergy. The unconverted heat or thermal energy accounts forapproximately 65 to 85% of the energy released in the burner 528104. Theranges given herein are approximations and the ranges may vary dependingon the embodiment of water vapor distillation apparatus used in thesystem and the embodiment of the Stirling engine (or other generator)used in the system.

This heat is available to provide heating to the local environmentaround the power unit 528110 in two forms: a smaller flow of exhaust gasfrom the burner 528104 and a much larger flow of heat rejected at thecooler 528103 of the Stirling engine. Power unit 528110 may also bereferred to as an auxiliary power unit (APU). The exhaust gases arerelatively hot, typically 100 to 300° C., and represent 10 to 20% of thethermal energy produced by the Stirling engine 528101. The coolerrejects 80 to 90% of the thermal energy at 10 to 20° C. above theambient temperature. The heat is rejected to either a flow of water or,more typically, to the air via a radiator 528107. Stirling cycle engine528101 is preferably of a size such that power unit 528010 istransportable.

As shown in FIG. 528B, Stirling engine 528101 is powered directly by aheat source such as burner 528104. Burner 528104 combusts a fuel toproduce hot exhaust gases which are used to drive the Stirling engine528101. A burner control unit 528109 is coupled to the burner 528104 anda fuel canister 528110. Burner control unit 528109 delivers a fuel fromthe fuel canister 528110 to the burner 528104. The burner controller528109 also delivers a measured amount of air to the burner 528104 toadvantageously ensure substantially complete combustion. The fuelcombusted by burner 528104 is preferably a clean burning andcommercially available fuel such as propane. A clean burning fuel is afuel that does not contain large amounts of contaminants, the mostimportant being sulfur. Natural gas, ethane, propane, butane, ethanol,methanol and liquefied petroleum gas (“LPG”) are all clean burning fuelswhen the contaminants are limited to a few percent. One example of acommercially available propane fuel is HD-5, an industry grade definedby the Society of Automotive Engineers and available from Bernzomatic.In accordance with an embodiment of the system, and as discussed in moredetail below, the Stirling engine 528101 and burner 528104 providesubstantially complete combustion in order to provide high thermalefficiency as well as low emissions. The characteristics of highefficiency and low emissions may advantageously allow use of power unit528010 indoors.

Generator 528102 is coupled to a crankshaft (not shown) of Stirlingengine 528101. It should be understood to one of ordinary skill in theart that the term generator encompasses the class of electric machinessuch as generators wherein mechanical energy is converted to electricalenergy or motors wherein electrical energy is converted to mechanicalenergy. The generator 528102 is preferably a permanent magnet brushlessmotor. A rechargeable battery 528113 provides starting power for thepower unit 528010 as well as direct current (“DC”) power to a DC poweroutput 528112. In a further embodiment, APU 528010 also advantageouslyprovides alternating current (“AC”) power to an AC power output 528114.An inverter 528116 is coupled to the battery 528113 in order to convertthe DC power produced by battery 528113 to AC power. In the embodimentshown in FIG. 528B, the battery 528113, inverter 528116 and AC poweroutput 528114 are disposed within an enclosure 528120.

Utilization of the exhaust gas generated in the operation of power unit528010 is now described with reference to the schematic depiction of anembodiment of the system shown in FIG. 528C. Burner exhaust is directedthrough a heat conduit 528016 into enclosure 528504 of the water vapordistillation apparatus unit designated generally by numeral 528012. Heatconduit 528016 is preferably a hose that may be plastic or corrugatedmetal surrounded by insulation, however all means of conveying exhaustheat from power unit 528010 to water purification unit 528012 are withinthe scope of the system. The exhaust gas, designated by arrow 528502,blows across a heat exchanger 528506 (in the exemplary embodiment, ahose-in-hose heat exchanger is used, in other embodiments, a finned heatexchanger is used), thereby heating the source water stream 528508 as ittravels to the water vapor distillation (which is also referred toherein as a “still”) evaporator 528510. The hot gas 528512 that fillsthe volume surrounded by insulated enclosure 528504 essentially removesall thermal loss from the still system since the gas temperature withinthe insulated cavity is hotter than surface 528514 of the still itself.Thus, there is substantially no heat flow from the still to the ambientenvironment, and losses on the order of 75 W for a still of 10gallon/hour capacity are thereby recovered. A microswitch 528518 sensesthe connection of hose 528016 coupling hot exhaust to purification unit528012 so that operation of the unit may account for the influx of hotgas.

In accordance with alternate embodiments adding heat to exhaust stream528502 is within the scope of the system, whether through addition of apost-burner (not shown) or using electrical power for ohmic heating.

During initial startup of the system, power unit 528010 is activated,providing both electrical power and hot exhaust. Warm-up of the still528012 is significantly accelerated since the heat exchanger 528506 isinitially below the dew point of the moisture content of the exhaust,since the exhaust contains water as a primary combustion product. Theheat of vaporization of this water content is available to heat sourcewater as the water condenses on the fins of the heat exchanger. The heatof vaporization supplements heating of the heat exchanger by convectionof hot gas within the still cavity. For example, in the fin heatexchanger embodiment, heating of the fins by convection continues evenafter the fins reach the dew point of the exhaust.

In accordance with other embodiments of the system, power unit 528010and still 528012 may be further integrated by streaming water from thestill through the power unit for cooling purposes. The use of sourcewater for cooling presents problems due to the untreated nature of thewater. Whereas using the product water requires an added complexity ofthe system to allow for cooling of the power unit before the still haswarmed up to full operating conditions.

Referring again to FIG. 44, other embodiments may include the use ofadditives in solid form, wherein such additives could be embedded in atime-release matrix inserted into the flow-through channel of intake4404. In one particular embodiment, replacement additive would need tobe inserted periodically by the user. In yet another embodiment, apowder form of an additive could be added in a batch system wherein thepowder is added, for example in tablet form, to an external reservoircontaining water to be purified wherein the additive is uniformly mixed,similar to the batch system for adding liquid additives described above.

Still referring to FIG. 44, pre-treatment of the source water may occurprior to or within intake 4404. Pre-treatment operations may include,but is not limited to gross-filtering; treatment with chemical additivessuch as polyphosphates, polyacetates, organic acids, or polyaspartates;and electrochemical treatment such as an oscillating magnetic field oran electrical current; degassing; and UV treatment. Additives may beadded in liquid form to the incoming liquid stream using a continuouspumping mechanism such as a roller pump or pulsatile pump, including astandard diaphragm pump or piezoelectric diaphragm pump. Alternatively,the additives may be added by a semi-continuous mechanism using, forexample, a syringe pump, which would require a re-load cycle, or a batchpumping system, wherein a small volume of the additive would be pumpedinto a holding volume or reservoir external to the system that uniformlymixes the additive with the liquid before the liquid flows into thesystem. It is also envisioned that the user could simply drop aprescribed volume of the additive into, for example, a bucket containingthe liquid to be purified. Liquid additive may be loaded as either alifetime quantity (i.e., no consumables for the life of the machine), oras a disposable amount requiring re-loading after consumption.

Still referring to FIG. 44, similarly post-treatment of the productwater may occur preferably within an external output region (not shown).Post-treatment operations may include, but is not limit to tasteadditives such as sugar-based additives for sweetening, acids fortartness, and minerals. Other additives, including nutrients, vitamins,stabilized proteins such as creatinine, and fats, and sugars may also beadded. Such additives may be added either in liquid or solid form,whether as a time-release tablet through which the output liquid flowsor a powder added to an external reservoir such as through a batchsystem. Alternatively, the additive may be added to the output liquidvia an internal coating of a separate collection reservoir or container,for example, by leaching or dissolution on contact. In such embodiments,the ability to detect purified liquid with and without the additive maybe preferred. Detection systems in accordance with various embodimentsinclude pH analysis, conductivity and hardness analysis, or otherstandard electrical-based assays. Such detection systems allow forreplacement of additives, as needed, by triggering a signal mechanismwhen the additive level/quantity is below a pre-set level, or isundetectable.

In another embodiment, liquid characteristics, such as for example waterhardness, is monitored in the output and may be coupled with anindicator mechanism which signals that it is preferable to addappropriate additives.

In yet another embodiment, ozone is systemically generated using, forexample, electric current or discharge methods, and added to the outputproduct for improved taste. Alternatively, air may be pumped through aHEPA filter bubbling through the product water to improve palatabilityof the water.

Similarly, it is envisioned that other embodiments may include means fordetecting nucleic acids, antigens and bio-organisms such as bacteria.Examples of such detection means include nanoscale chemistry andbiochemistry micro-arrays known in the field and currently commerciallyavailable. Such arrays may also be used to monitor the presence and/orabsence of nutrients and other additives in the purified product, asdiscussed above.

In another embodiment, UV treatment may be used post-purification, forexample in a storage barrel or other container, to aid in maintenance ofthe purified product.

While the principles of the invention have been described herein, it isto be understood by those skilled in the art that this description ismade only by way of example and not as a limitation as to the scope ofthe invention. Other embodiments are contemplated within the scope ofthe present invention in addition to the exemplary embodiments shown anddescribed herein. Modifications and substitutions by one of ordinaryskill in the art are considered to be within the scope of the presentinvention.

1. A fluid vapor distillation apparatus comprising: a source fluidinput; an evaporator condenser apparatus comprising: a substantiallycylindrical housing; and a plurality of tubes in said housing, wherebysaid source fluid input is fluidly connected to said evaporatorcondenser and said evaporator condenser transforms source fluid intosteam and transforms compressed steam into product fluid; a heatexchanger fluidly connected to said source fluid input and a productfluid output, said heat exchanger comprising: an outer tube; and atleast one inner tube; and a regenerative blower fluidly connected tosaid evaporator condenser, whereby said regenerative blower compressessteam, and whereby the compressed steam flows to the evaporativecondenser where compressed steam is transformed into product fluid. 2.The apparatus of claim 1 wherein the heat exchanger is disposed aboutsaid housing of said evaporator condenser.
 3. The apparatus of claim 1wherein the heat exchanger further comprising wherein said outer tube isa source fluid flow path and said at least one inner tube is a productfluid flow path.
 4. The apparatus of claim 3 wherein said heat exchangerfurther comprising at least three inner tubes.
 5. The apparatus of claim4 wherein said at least three inner tubes are twined to form asubstantially helical shape.
 6. The apparatus of claim 5 wherein saidheat exchanger further comprising two ends, and at each end a connectoris attached, whereby said connectors form a connection to the evaporatorcondenser.
 7. The apparatus of claim 1 wherein said evaporator condensertubes further comprising packing inside the tubes.
 8. The apparatus ofclaim 7 wherein said packing is a rod.
 9. The apparatus of claim 1wherein said evaporator condenser further comprising a steam chestfluidly connected to said plurality of tubes.
 10. The apparatus of claim1 wherein said regenerative blower further comprising an impellerassembly driven by a magnetic drive coupling.
 11. A water vapordistillation system comprising: a water vapor distillation apparatuscomprising: a source fluid input; an evaporator condenser apparatuscomprising: a substantially cylindrical housing; and a plurality oftubes in said housing, whereby said source fluid input is fluidlyconnected to said evaporator condenser and said evaporator condensertransforms source fluid into steam and transforms compressed steam intoproduct fluid; a heat exchanger fluidly connected to said source fluidinput and a product fluid output, said heat exchanger comprising: anouter tube; and at least one inner tube; and a regenerative blowerfluidly connected to said evaporator condenser, whereby saidregenerative blower compresses steam, and whereby the compressed steamflows to the evaporative condenser where compressed steam is transformedinto product fluid; a Stirling engine electrically connected to saidwater vapor distillation apparatus, wherein said Stirling engine atleast partially powers said water vapor distillation apparatus.
 12. Thewater vapor distillation system of claim 11 wherein said Stirling enginecomprising: at least one rocking drive mechanism comprising: a rockingbeam having a rocker pivot; at least one cylinder; at least one piston,the piston housed within a respective cylinder whereby the piston iscapable of substantially linearly reciprocating within the respectivecylinder; and at least one coupling assembly having a proximal end and adistal end, the proximal end being connected to the piston and thedistal end being connected to the rocking beam by an end pivot, wherebylinear motion of the piston is converted to rotary motion of the rockingbeam; a crankcase housing the rocking beam and housing a first portionof the coupling assembly; a crankshaft coupled to the rocking beam byway of a connecting rod, whereby the rotary motion of the rocking beamis transferred to the crankshaft; a working space housing the at leastone cylinder, the at least one piston and a second portion of thecoupling assembly; and a seal for sealing the workspace from thecrankcase.
 13. The water vapor distillation system of claim 12 whereinthe seal is a rolling diaphragm.
 14. The water vapor distillation systemof claim 12 wherein the coupling assembly further comprising: a pistonrod; and a link rod, the piston rod and link rod coupled together by acoupling means.
 15. The water vapor distillation system of claim 12further comprising a lubricating fluid pump in the crankcase.
 16. Thewater vapor distillation system of claim 12 wherein the heat exchangeris disposed about the housing of the evaporator condenser.
 17. The watervapor distillation system of claim 12 wherein the heat exchanger furthercomprising wherein the outer tube is a source fluid flow path and the atleast one inner tube is a product fluid flow path.
 18. The water vapordistillation system of claim 17 wherein the heat exchanger furthercomprising at least three inner tubes.
 19. The water vapor distillationsystem of claim 12 wherein the evaporator condenser further comprising asteam chest fluidly connected to the plurality of tubes.
 20. The watervapor distillation system of claim 12 wherein the regenerative blowerfurther comprising an impeller assembly driven by a magnetic drivecoupling.